Advanced methods to mechanically isolate stromal vascular fraction: A concise review

Adipose tissue is a highly attractive reservoir of stem cells due to its accessibility and abundance, and the SVF within it holds great promise for stem cell-based therapies. The use of mechanical methods for SVF isolation from adipose tissue is preferred over enzymatic methods, as it can be readily applied in clinical settings without additional processing steps. However, there is a lack of consensus on the optimal approach for mechanically isolating SVF. This comprehensive review aims to present and compare the latest mechanical isolation methods for SVF from adipose tissue, including centrifugation, filtration/washing, emulsification, vibration, and mincing/adiponizing. Each of these methods possesses unique advantages and limitations, and yet, no conclusive evidence has emerged demonstrating the superiority of one approach over the others, primarily due to the dearth of well-controlled prospective studies in this field.

Recommended centrifuge method: Specific grain size separation in the <63 µm fraction of marine sediments

The isolation of specific grain size classes of lithogenic samples and biogenic carbonate from the <63 µm fraction (i.e. clay and silt) of marine sediment is often a prerequisite to further pre-treatments and/or analytical measurements for palaeoceanographic studies. Established techniques employed have included sieving, settling and micro-filtration (and/or a combination of these). However, these methods often use significant amounts of bulk sediment (often up to ∼3 g) and/or require considerable amounts of time during sediment processing (ranging from 48 h to 3 weeks) to isolate a size specific class for further analyses. Here, we build on previous approaches to isolate three grain size classes (e.g. <2 µm, clay; 2-10 µm, fine silt; and 10-63 µm, coarse silt) from the <63 µm fraction of marine sediment with the aid of a centrifuge at varying revolutions per minute using Stokes' Law. We show the utility of our approach using two common sediment types dominated by (i) lithogenic and (ii) biogenic carbonate (specifically coccoliths) components of marine sediment cores. Our method reduces the amount of sample material required to 1-2 g to provide an isolated clay fraction (or other targeted size fraction) and decreases the sample processing time (to ∼1 hour) to enable high throughput of analysis, when compared to previous techniques for palaeoceanographic proxy measurements.•We recommend a more straightforward grain size isolation method for lithogenic sediment and biogenic carbonate sediment types•Isolating commonly targeted grain size fractions for palaeoceanographic studies using a centrifuge.

The power of centrifugation: How to extract microplastics from soil with high recovery and matrix removal efficiency

Understanding the occurrence and transformation of microplastics when released into the environment is essential for risk assessment. The use of biodegradable polymers in agriculture can help to reduce microplastic accumulation in soil, since released fragments of such materials are not persistent and are further transformed into CO2 and biomass (Wohlleben et al., 2023). To be able to monitor the fragmentation and biodegradation of these materials in soil, a validated extraction protocol is needed, which does not induce changes in the chemical and particle properties, additionally it should show high recoveries and matrix removal efficiency. A density-based extraction method in the centrifuge has the potential to remove a high amount of the soil matrix and is very selective for the polymer at the same time. Here we developed an efficient and non-destructive extraction protocol for biodegradable fragments from different soils using sequential centrifugation steps with varying densities and a freezing approach for sample collection. Although the focus of the present study was on biodegradable fragments, the technique can also be used for other types of microplastics with similar or lower density than the one tested for the method validation, but additional recovery tests for the target analyte are recommended.•A density-based extraction method for microplastics from soil, validated by recovery and stability tests using biodegradable polymers•Vessel changes and harsh chemical treatments are kept to a minimum.

AI Driven Lab-on-chip Cartridge for Automated Urinalysis

After haematology, urinalysis is the most common biological test performed in clinical settings. Hence, simplified workflow and automated analysis of urine elements are of absolute necessities. In the present work, a novel lab-on-chip cartridge (Gravity Sedimentation Cartridge) for the auto analysis of urine elements is developed. The GSC consists of a capillary chamber that uptakes a raw urine sample by capillary force and performs particles and cells enrichment within 5 min through a gravity sedimentation process for the microscopic examination. Centrifugation, which is necessary for enrichment in the conventional method, was circumvented in this approach. The AI100 device (Image based autoanalyzer) captures microscopic images from the cartridge at 40x magnification and uploads them into the cloud. Further, these images were auto-analyzed using an AI-based object detection model, which delivers the reports. These reports were available for expert review on a web-based platform that enables evidence-based tele reporting. A comparative analysis was carried out for various analytical parameters of the data generated through GSC (manual microscopy, tele reporting, and AI model) with the gold standard method. The presented approach makes it a viable product for automated urinalysis in point-of-care and large-scale settings.

Combining and concentrating nanocelluloses for cryogels with remarkable strength and wet resilience

Cellulose cryogels are promising eco-friendly materials that exhibit low density, high porosity, and renewability. However, the applications of these materials are limited by their lower mechanical and water resistance compared to petrochemical-based lightweight materials. In this work, nanocelluloses were functionalized with cationic and anionic groups, and these nanomaterials were combined to obtain strong and water-resilient cryogels. To prepare the cryogels, anionic and cationic micro- and nanofibrils (CNFs) were produced at three different sizes and combined in various weight ratios, forming electrostatic complexes. The complex phase was concentrated by centrifugation and freeze-dried. Porous and open cellular structures were assembled in all compositions tested (porosity >90 %). Compressive testing revealed that the most resistant cryogels (1.7 MPa) were obtained with equivalent amounts of negatively and positively charged CNFs with lengths between 100 and 1200 nm. The strength at this condition was achieved as CNF electrostatic complexes assembled in thick cells, as observed by synchrotron X-ray tomography. In addition to mechanical strength, electrostatic complexation provided remarkable structural stability in water for the CNF cryogels, without compromising their biodegradability. This route by electrostatic complexation is a practical strategy to combine and concentrate nanocelluloses to tailor biodegradable lightweight materials with high strength and wet stability.

Mechanical Purification of Lipofilling: The Relationship Between Cell Yield, Cell Growth, and Fat Volume Maintenance

BACKGROUND

The mechanical manipulations of fat tissue represented from centrifugation, filtration, washing, and fragmentation were considered the most effective strategies aiming to obtain purified lipofilling with different impacts both in terms of adipose-derived stem cells amount contained in stromal vascular fraction, and fat volume maintenance.

OBJECTIVES

The present work aimed to report results in fat volume maintenance obtained by lipofilling purification based on the combined use of washing and filtration, in a clinical study, and to deeply investigate the adipose-derived stem cells yield and growth capacity of the different stromal vascular fraction extraction techniques with an in vitro approach.

METHODS

A preliminary prospective, case-control study was conducted. 20 patients affected by face and breast soft tissue defects were treated with lipofilling and divided into two groups: n = 10 patients (study group) were treated with lipofilling obtained by washing and filtration procedures, while n = 10 (control group) were treated with lipofilling obtained by centrifugation according to the Coleman technique. 6 months after the lipofilling, the volume maintenance percentage was analyzed by clinical picture and magnetic resonance imaging comparisons. Additionally, extracted stromal vascular fraction cells were also in vitro analyzed in terms of adipose-derived stem cell yield and growth capacity.

RESULTS

A 69% ± 5.0% maintenance of fat volume after 6 months was observed in the study group, compared with 44% ± 5.5% in the control group. Moreover, the cellular yield of the control group resulted in 267,000 ± 94,107 adipose-derived stem cells/mL, while the study group resulted in 528,895 ± 115,853 adipose-derived stem cells /mL, with a p-value = 0.1805. Interestingly, the study group showed a fold increase in cell growth of 6758 ± 0.7122, while the control group resulted in 3888 ± 0.3078, with a p < 0.05 (p = 0.0122).

CONCLUSIONS

The comparison of both groups indicated that washing and filtration were a better efficient system in lipofilling preparation, compared to centrifugation, both in terms of volume maintenance and adipose-derived stem cell growth ability.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .

Logistic analysis of delayed reporting of emergency blood potassium and comparison of improved outcomes

Potassium testing is an essential test in emergency medicine. Turnaround time (TAT) is the time between specimen receipt by the laboratory and the release of the test report. A brief in-laboratory TAT increases emergency department effectiveness. Optimizing processes to shorten TAT using other tools requires extensive time, resources, training, and support. Therefore, we aimed to find a convenient way to shorten TAT, identify risk factors affecting the timeliness of emergency potassium test reporting, and verify the intervention's effects. The dependent variable was emergency potassium reporting time > 30 or < 30 min. Logistic analysis was performed on monitorable factors, such as sex, age, potassium results, number of items, specimen processing time (including centrifugation and time before specimen loading), critical value ratio, instrument status, shift where the report was issued, specimen status, and work experience, as independent variables. In the multivariate analysis, work experience, instrument failure rate, and specimen processing time were risk factors for emergency blood potassium reporting exceeding 30 min. Improvement measures were implemented, significantly decreasing the timeout rate for acute potassium reporting. Our study confirms the usefulness of logistics in reducing the time required to report potassium levels in the emergency department, providing a new perspective on quality management.

Enhancing the dispersibility of Gelidium amansii-derived microfibrillated cellulose through centrifugal fractionation

Hydrothermal pretreatment is useful for microfibrillated cellulose (MFC) preparation due to its safety, but the remaining hemicellulose might affect MFC properties. This study aimed to investigate the effect of centrifugation time on hemicellulose removal and the physicochemical properties of MFC obtained after hydrothermal pretreatment and micro-fibrillation. In this study, centrifugation was applied to the MFC suspension at varying duration times. Composition analysis and Fourier transform infrared spectra indicated that fractionated MFC has no hemicellulose content after 10, 20, and 30 min centrifugation. It also showed an approximately 5 times higher than 0.5 % g/g of initial solid concentration, indicated by a lower gel concentration point, than unfractionated MFC. Scanning electron microscope images of the fractionated MFC for 30 min (MFC2C) presented thin, long cellulose fibrils of 517 nm in average diameter and 635-10,000 nm in length that induced a slower sedimentation rate. MFC2C dispersion was also improved by autoclave sterilization by regulating cellulose structure, rheology, and crystallinity. As a result, MFC dispersibility can be enhanced by removing hemicellulose through simple centrifugation.

High-Speed Centrifugation Efficiently Removes Immunogenic Elements in Osteochondral Allografts

OBJECTIVES

The current clinical pulse lavage technique for flushing fresh osteochondral allografts (OCAs) to remove immunogenic elements from the subchondral bone is ineffective. This study aimed to identify the optimal method for removing immunogenic elements from OCAs.

METHODS

We examined five methods for the physical removal of immunogenic elements from OCAs from the femoral condyle of porcine knees. We distributed the OCAs randomly into the following seven groups: (1) control, (2) saline, (3) ultrasound, (4) vortex vibration (VV), (5) low-pulse lavage (LPL), (6) high-pulse lavage (HPL), and (7) high-speed centrifugation (HSC). OCAs were evaluated using weight measurement, micro-computed tomography (micro-CT), macroscopic and histological evaluation, DNA quantification, and chondrocyte activity testing. Additionally, the subchondral bone was zoned to assess the bone marrow and nucleated cell contents. One-way ANOVA and paired two-tailed Student's t-test are used for statistical analysis.

RESULTS

Histological evaluation and DNA quantification showed no significant reduction in marrow elements compared to the control group after the OCAs were treated with saline, ultrasound, or VV treatments; however, there was a significant reduction in marrow elements after LPL, HPL, and HSC treatments. Furthermore, HSC more effectively reduced the marrow elements of OCAs in the middle and deep zones compared with LPL (p < 0.0001) and HPL (p < 0.0001). Macroscopic evaluation revealed a significant reduction in blood, lipid, and marrow elements in the subchondral bone after HSC. Micro-CT, histological analyses, and chondrocyte viability results showed that HSC did not damage the subchondral bone and cartilage; however, LPL and HPL may damage the subchondral bone.

CONCLUSION

HSC may play an important role in decreasing immunogenicity and therefore potentially increasing the success of OCA transplantation.

Comparison of adsorption-extraction (AE) workflows for improved measurements of viral and bacterial nucleic acid in untreated wastewater

The lack of standardized methods and large differences in virus concentration and extraction workflows have hampered Severe Acute Respiratory Syndrome (SARS-CoV-2) wastewater surveillance and data reporting practices. Numerous studies have shown that adsorption-extraction (AE) method holds promise, yet several uncertainties remain regarding the optimal AE workflow. Several procedural components may influence the recovered concentrations of target nucleic acid, including membrane types, homogenization instruments, speed and duration, and lysis buffer. In this study, 42 different AE workflows that varied these components were compared to determine the optimal workflow by quantifying endogenous SARS-CoV-2, human adenovirus 40/41 (HAdV 40/41), and a bacterial marker gene of fecal contamination (Bacteroides HF183). Our findings suggest that the workflow chosen had a significant impact on SARS-CoV-2 concentrations, whereas it had minimal impact on HF183 and no effect on HAdV 40/41 concentrations. When comparing individual components in a workflow, such as membrane type (MF-Millipore™ 0.45 μm MCE vs. Isopore™ 0.40 μm), we found that they had no impact on SARS-CoV-2, HAdV 40/41, and HF183 concentrations. This suggests that at least some consumables and equipment are interchangeable. Buffer PM1 + TRIzol-based workflows yielded higher concentrations of SARS-CoV-2 than other workflows. HF183 concentrations were higher in workflows without chloroform. Similarly, higher homogenization speeds (5000-10,000 rpm) led to increased concentrations of SARS-CoV-2 and HF183 but had no effect on HAdV 40/41. Our findings indicate that minor enhancements to the AE workflow can improve the recovery of viruses and bacteria from the wastewater, leading to improved outcomes from wastewater surveillance efforts.

Isolation of Extracellular Vesicles Using Formulas to Adapt Centrifugation to Different Centrifuges

Extracellular vesicles (EVs) are small lipid bilayer vesicles released by cells to facilitate cell-to-cell communication. To study their biological roles and functions, they need to be isolated and purified, which can be achieved through a variety of methods. Here, we describe different methods for isolating and purifying EVs, with a focus on calculating the required g-force and centrifugation time with different centrifuges and rotors. We have compiled key formulas and tested predicted parameters for EV acquisitions to provide a comprehensive guide for EV isolation.

Isolation of Double-Stranded RNAs by Lithium Chloride Fractionation

This procedure provides a comprehensive method for isolating double-stranded RNA (dsRNA) that relies on the different solubility of various nucleic acids in lithium chloride (LiC1). The approach offers several notable advantages including simplicity, avoidance of enzymatic treatments, and the ability to obtain relatively high yields of undegraded dsRNA over other conventional techniques. Moreover, it allows for the separation of different groups of cellular and viral nucleic acids from a single tissue sample. This method was further improved to increase the purity of dsRNA using plant tissues infected by RNA viruses.

Parry-Romberg Syndrome: Successful Result in a Single Procedure Combining Silicone Implant and Structural Fat Grafting for Severe Facial Deformity

Background

Parry-Romberg syndrome (PRS) is an enigmatic and acquired degenerative condition. It is characterized by a gradual and progressive facial hemiatrophy, after which facial deformities appear unexpectedly in a stable state. The degree of disfigurement depends on tissue involvement, illness onset, and duration. Nowadays, non-invasive treatments with lower morbidity, such as structured fat grafting (SFG) are preferred over traditional operations such as free flaps and bone grafts. However, for severe cases of PRS, multiple sessions of SFG are required.

Case study

Despite the therapeutic failure that a 20-year-old lady had suffered after five previous conventional surgical procedures, the outcome was successful after only one surgical therapy employing a particular combination of SFG and malar silicone elastomers implant (SI).

Conclusion

The author highlights the interest in a combination of non-invasive procedures using SFG and malar augmentation with SI to repair large volume loss while improving symmetry and skin texture. Otherwise, the role of adipose-derived stem cells in fat survival is crucial and should be the focus of future studies and the key to technological advancement.

Guidelines for an optimized differential centrifugation of cells

Literature reviews reveal a significant deficiency in conceptual comprehension concerning centrifugation, a crucial step in both medical and research protocols. The arbitrary fluctuations in centrifugal forces present a potential threat to the reproducibility of results. To address this, we propose concise guidelines that integrate key factors such as temperature, osmolarity, fluid volume, and viscosity. These guidelines aim to enhance comprehension of optimal sedimentation conditions for cell suspensions. Additionally, we introduce a standardized protocol for determining the optimal RCF and centrifugation time. The goal is to maximize sedimentation efficiency while minimizing cell damage, contributing to a universally applicable and reproducible method in centrifugation practices.

Virtual reality as a countermeasure for astronaut motion sickness during simulated post-flight water landings

Entry motion sickness (EMS) affects crewmembers upon return to Earth following extended adaptation to microgravity. Anticholinergic pharmaceuticals (e.g., Meclizine) are often taken prior to landing; however, they have operationally adverse side effects (e.g., drowsiness). There is a need to develop non-pharmaceutical countermeasures to EMS. We assessed the efficacy of a technological countermeasure providing external visual cues following splashdown, where otherwise only nauseogenic internal cabin visual references are available. Our countermeasure provided motion-congruent visual cues of an Earth-fixed scene in virtual reality, which was compared to a control condition with a head-fixed fixation point in virtual reality in a between-subject design with 15 subjects in each group. We tested the countermeasure's effectiveness at mitigating motion sickness symptoms at the end of a ground-based reentry analog: approximately 1 h of 2Gx centrifugation followed by up to 1 h of wave-like motion. Secondarily, we explored differences in vestibular-mediated balance performance between the two conditions. While Motion Sickness Questionnaire outcomes did not differ detectably between groups, we found significantly better survival rates (with dropout dictated by reporting moderate nausea consecutively over 2 min) in the visual countermeasure group than the control group (79% survival vs. 33%, t(14) = 2.50, p = 0.027). Following the reentry analogs, subjects demonstrated significantly higher sway prior to recovery (p = 0.0004), which did not differ between control and countermeasure groups. These results imply that providing motion-congruent visual cues may be an effective mean for curbing the development of moderate nausea and increasing comfort following future space missions.

Investigation of three common centrifugation protocols for platelet-rich fibrin (PRF) as a bio-carrier for ampicillin/sulbactam: a prospective trial

OBJECTIVES

Different platelet-rich fibrin (PRF) protocols exist and are known to differ in resulting mechanical and bioactive properties. Centrifugation parameters may also influence drug release, in particular antibiotics, when using PRF as a bio-carrier. We thus evaluated three common protocols regarding effects on the bio-carrier properties.

MATERIALS AND METHODS

In a prospective trial comprising 33 patients, we compared different protocols for PRF as a bio-carrier for ampicillin/sulbactam (SAM). Blood samples were taken shortly after a single dose of ampicillin/sulbactam (2 g/1 g) was administered to patients intravenously. PRF was obtained by centrifugation and three protocols were used: protocol A (1300 rpm, 8 min, RCF-max = 208 g), B (2300 rpm, 12 min, RCF-max = 652 g), and C (1500 rpm, 14 min, RCF-max = 276 g). The antibacterial activity of PRF was investigated against five oral species in vitro, based on agar diffusion methodology.

RESULTS

The study demonstrates that a single dose of SAM is sufficient to reach high concentrations in PRF in all protocols (150 µg/ml), which is comparable to the plasma SAM concentration. Antibacterial activity was inferred from the diameter of inhibition zones seen in agar diffusion tests using PRF discs. Protocol B resulted in the largest inhibition zones. One-way ANOVA revealed statistically improved results for protocol B for some bacteria.

CONCLUSIONS

The study provides valuable data on PRF antibiotic enrichment, notably SAM. A single dose of SAM is sufficient to reach clinically relevant concentrations in PRF.

CLINICAL RELEVANCE

These findings potentially extend the application of PRF, for example in patients with osteonecrosis of the jaw or in oral surgery (e.g., stick bone).

Adjunctive effect of collagen membrane coverage to L-PRF in the treatment of periodontal intrabony defects: a randomized controlled clinical trial with biochemical assessment

BACKGROUND

The innovation of leukocyte platelet-rich fibrin (L-PRF) has added enormous impact on wound healing dynamics especially the field of periodontal regeneration. The release of growth factors (GF) is thought to improve the clinical outcomes in infrabony defects. The aim of this study was to evaluate the clinical effect of covering L-PRF contained infrabony defects with collagen membranes (CM), and to compare their GF release profile to uncovered L-PRF defects and open flap debridement (OFD).

METHODS

Thirty non- smoking patients with infrabony pockets participated to be randomly assigned to OFD group (n = 10), L-PRF group (n = 10), or L-PRF protected CM group (n = 10). Plaque index (PI), gingival index (GI), probing depth (PD), clinical attachment level (CAL) and the radiographic defect base fill (DBF) were measured at baseline and at 6 month following surgical intervention. Gingival crevicular fluid samples were obtained on days 1, 3, 5, 7, 14, 21 and 30 days following surgery for the Platelet Derived Growth Factor-BB (PDGF-BB) and Vascular Endothelial Growth Factors (VEGF) release profile evaluation.

RESULTS

For all patients, a statistically significant (P ≤ 0.05) reduction in PI, GI, PD and CAL were reported throughout the study period. Differences between the three treatment modalities were not statistically significant. PRF + CM showed a statistically significant DBF compared to OFD and L-PRF groups at follow up. Quantitative analysis of PDGF-BB and VEGF levels demonstrated a statistically significant (P < 0.001) decline between measurement intervals for all groups with no statistically significant differences between the three groups.

CONCLUSION

Within the limitations of this study, L-PRF coverage with CM may augment defect base fill through its mechanical protective effect without enhancement in the release profile of VEGF and PDGF. The non-significant intergroup differences question the validity of the claimed extra physiologic concentration of GF offered by L-PRF harvests.

TRIAL REGISTRATION

The present study was registered at ClinicalTrials.gov (NCT05496608), (11/08/2022).

Size-exclusion chromatography for the characterization of urinary extracellular vesicles

In recent years, extracellular vesicles (EVs) have gained attention for their potential as biomarkers for the early diagnosis and treatment of various diseases. Traditionally, EV isolation has relied exclusively on ultracentrifugation. However, alternative enrichment methods such as size-exclusion chromatography (SEC) and polyethylene glycol-based precipitation have been introduced. This study utilized SEC as a characterization tool to assess the efficiency of EV isolation. Urinary EVs isolated from human urine using centrifugation (40,000 × g) were analyzed using an SEC column with a pore size of 1000 Å, an inner diameter of 7.8 mm, and a length of 300 mm. The EVs were detected sequentially using UV (280 nm) and fluorescence (λex/em = 550 nm/565 nm); the EVs were observed at approximately 6 min, while the proteins were observed at approximately 12 min. The repeated centrifugation enrichment steps resulted in an increase in EV peaks and a decrease in protein peaks. SEC analysis of the enriched EV samples confirmed that a four-cycle repetition of centrifugation is necessary for successful EV enrichment and removal of non-EV proteins from 40 mL of human urine.

Purification processes of polymeric nanoparticles: How to improve their clinical translation?

Polymeric nanoparticles, as revolutionary nanomedicines, have offered a new class of diagnostic and therapeutic solutions for a multitude of diseases. With its immense potential, the world witnesses the new age of nanotechnology after the COVID-19 vaccines were developed based on nanotechnology. Even though there are countless benchtop research studies in the nanotechnology world, their integration into commercially available technologies is still restricted. The post-pandemic world demands a surge of research in the domain, which leaves us with the fundamental question: why is the clinical translation of therapeutic nanoparticles so restricted? Complications in nanomedicine purification, among other things, are to blame for the lack of transference. Polymeric nanoparticles, owing to their ease of manufacture, biocompatibility, and enhanced efficiency, are one of the more explored domains in organic-based nanomedicines. Purification of nanoparticles can be challenging and necessitates tailoring the available methods in accordance with the polymeric nanoparticle and impurities involved. Though a number of techniques have been described, there are no available guidelines that help in selecting the method to better suit our requirements. We encountered this difficulty while compiling articles for this review and looking for methods to purify polymeric nanoparticles. The currently accessible bibliography for purification techniques only provides approaches for a specific type of nanomaterial or sometimes even procedures for bulk materials, that are not fully relevant to nanoparticles. In our research, we tried to summarize the available purification techniques using the approach of A.F. Armington. We divided the purification systems into two major classes, namely: phase separation-based techniques (based on the physical differences between the phases) and matter exchange-based techniques (centered on physicochemical induced transfer of materials and compounds). The phase separation methods are based on either using nanoparticle size differences to retain them on a physical barrier (filtration techniques) or using their densities to segregate them (centrifugation techniques). The matter exchange separation methods rely on either transferring the molecules or impurities across a barrier using simple physicochemical phenomena, like the concentration gradients (dialysis method) or partition coefficients (extraction technique). After describing the methods in detail, we highlight their advantages and limitations, mainly focusing on preformed polymer-based nanoparticles. Tailoring a purification strategy takes into account the nanoparticle structure and its integrity, the method selected should be suited for preserving the integrity of the particles, in addition to conforming to the economical, material and productivity considerations. In the meantime, we advocate the use of a harmonized international regulatory framework to define the adequate physicochemical and biological characterization of nanomedicines. An appropriate purification strategy serves as the backbone to achieving desired characteristics, in addition to reducing variability. As a result, the present review aspires to serve as a comprehensive guide for researchers, who are new to the domain, as well as a synopsis of purification strategies and analytical characterization methods used in preclinical studies.

Estimation of the Mechanical Properties of PRF in the Implant Surgery: An Original Research

Introduction

In many oral procedures that involve the implants, hair implantations, "Platelet-Rich Fibrin Membrane (PRF)" is commonly applied. The advantages are many. In this study, the mechanical resistance of PRF under resistance pull on a longitudinal axis was assessed and compared.

Material and Methods

For the current in vitro study, 60 volunteers donated each 10 ml of their blood and hence a total volume of 600 ml of blood was procured that was analyzed for the current study. The total volume was grouped to three groups where they receive three resistance centrifugation forces of "F-200,600,800 m/s²." In each group, 20 samples were tested for each level of the G-resistance. Each group was further divided as two subgroups of different times of wait, where they were centrifuged at baseline time and after a stand of 30 minutes. On universal testing equipment, the PRF membranes were mechanically tensioned in order to determine each membrane's resistance force. These values were compared for any statistical variance using appropriate statistical tools keeping P < 0.05.

Results

Any applied force had no statistically significant effect on the centrifugation duration for membrane resistance. When the resistance was applied for the PRP samples immediately after they were procured, no significant variation was seen at all the grades of the centrifugation forces; consequently, the T30 group showed a statistically significant variance for the centrifugation forces applied (P = 0.04), with the highest value when the greatest force was applied. According to the results, the centrifugation waiting period could be determined based on the application requirement.

Conclusion

For immediate membrane usage, the centrifugation had no effect on resistance; however, after 30 minutes, a membrane with greater resistance was produced by applying more force.

Effects of carboxymethyl cellulose on the emulsifying, gel and digestive properties of myofibrillar protein-soybean oil emulsion

Improving the qualities of vegetable oil replaced animal fat meat products is particularly fascinating for the development of healthy meat products. This work was designed to investigate the effects of different carboxymethyl cellulose (CMC) concentrations (0.01 %, 0.05 %, 0.1 %, 0.2 %, and 0.5 %) on the emulsifying, gelation, and digestive properties of myofibrillar protein (MP)-soybean oil emulsions. The changes in MP emulsion characteristics, gelation properties, protein digestibility, and oil release rate were determined. Results demonstrated that CMC addition decreased the average droplet size and increased the apparent viscosity, storage modulus, and loss modulus of MP emulsions, and a 0.5 % CMC addition significantly increased the storage stability during 6 weeks. Lower CMC addition (0.01 % to 0.1 %) increased the hardness, chewiness, and gumminess of emulsion gel especially for the 0.1 % CMC addition, while higher CMC (0.5 %) content decreased the texture properties and water holding capacity of emulsion gels. The addition of CMC decreased protein digestibility during the gastric stage, and 0.01 % and 0.05 % CMC addition significantly decreased the free fatty acid release rate. In summary, the addition of CMC could improve the stability of MP emulsion and the texture properties of the emulsion gels, and decrease protein digestibility during the gastric stage.

Technological aspects of manufacturing and analytical control of biological nanoparticles

Extracellular vesicles (EVs) are cell-derived biological nanoparticles that gained great interest for drug delivery. EVs have numerous advantages compared to synthetic nanoparticles, such as ideal biocompatibility, safety, ability to cross biological barriers and surface modification via genetic or chemical methods. On the other hand, the translation and the study of these carriers resulted difficult, mostly because of significant issues in up-scaling, synthesis and impractical methods of quality control. However, current manufacturing advances enable EV packaging with any therapeutic cargo, including DNA, RNA (for RNA vaccines and RNA therapeutics), proteins, peptides, RNA-protein complexes (including gene-editing complexes) and small molecules drugs. To date, an array of new and upgraded technologies have been introduced, substantially improving EV production, isolation, characterization and standardization. The used-to-be "gold standards" of EV manufacturing are now outdated, and the state-of-art requires extensive revision. This review re-evaluates the pipeline for EV industrial production and provides a critical overview of the modern technologies required for their synthesis and characterization.

Comparison of single and double centrifugation methods for preparation of Platelet-Rich Plasma (PRP)

Objective

To compare the platelet count, platelet concentration/yield, residual Red blood cells (RBCs) and White blood cells (WBCs) counts in platelet-rich plasma (PRP) samples prepared from the single- and the double-centrifugation protocols.

Methods

It was a Cross-Sectional study, conducted at the Department of Hematology & Transfusion Medicine, The Children's Hospital and UCHS, Lahore from October 2021 to January 2022 including 50 voluntary, healthy individuals of age 20-45 years of both genders, after taking informed consent. Complete blood count analysis of all participants was done initially by drawing 3ml blood in EDTA vial. From all the participants, 20 ml venous blood sample was taken in syringes containing tri-sodium citrate and then shifted to harvest tubes. Group-I comprised of PRP samples prepared by single- centrifugation method. While Group-II samples were prepared by Double-centrifugation method consisting of soft and hard spin. The platelet, RBC and WBC counts in prepared PRP samples were determined by using automated SYSMEX XP-100 hematology analyzer. Platelet yield or Platelet concentration (%) was calculated for samples using formula. The data analysis was done using SPSS version 23.

Results

The mean PRP platelet count in Group-I was 594.6±157.4×103/μl whereas in Group-II was 923.06 ± 127.58×103/μl. In Group-I, the mean platelet concentration/yield in PRP was 175.75 ± 55.08% while in Group-II, it was 276.78 ± 112.7%. Significant difference was observed between the platelet counts and platelet concentration/yields from the PRP samples of two Group-s (p < 0.01). Significant difference between the WBCs count was also observed (p < 0.01) with higher WBCs in Group- I PRP. Residual RBCs were almost same among two Group-s.

Conclusions

The double centrifugation protocol resulted in higher platelet quantity and yield with less contamination by red and white blood cells than did the single centrifugation protocol for PRP preparation. So, double centrifugation method is beneficial in preparation of autologous as well as allogenic PRP.

Microalgal wastewater recycling: Suitability of harvesting methods and influence on growth mechanisms

Wastewater recycling helps address the challenge of microalgae biomass commercialization by allowing for efficient resource recovery. In this study, three conventional harvesting methods, including centrifugation, microfiltration, and flocculation sedimentation, were investigated to explore the effects of harvesting methods on the characteristics of recycled wastewater and the growth of microalgae to select a suitable harvesting method for the microalgal wastewater recycling system. During the wastewater recycling process, the least amount of accumulated substances was exhibited in the wastewater recycled by microfiltration, followed by centrifugation, and the most by flocculation sedimentation. After 4 batches of cultivation, microalgal biomass harvested from centrifugation wastewater and microfiltration wastewater was 21.26 % and 13.54 % higher than that from flocculation wastewater, respectively. Lipids, carbohydrates and pigments were all increased by varying degrees. Additionally, flocculation sedimentation was not suitable for the microalgal wastewater recycling process since the low residual nutrients, high salinity, and excessive algal organic matter severely inhibited the growth of microalgae. Under the regulation of phytohormones, microalgae increased their energy reserves, enhanced photosynthesis, and improved their defense capability to resist the increasing abiotic stress. This study provides scientific support for the selection of suitable harvesting technology during the microalgal wastewater recycling process.

Immunoprecipitation: Variations, Considerations, and Applications

Immunoprecipitation (IP) refers to methods of affinity chromatography that enrich and/or purify a specific protein from a complex mixture using a specific antibody immobilized on a solid support. Several operations and processes that are dependent on the isolation, concentration, and modification of proteins have seen improvement in their selectivity and separation based on the integration of IP-specific reactions into their workflows. This relatively simple principle has contributed significantly to our understanding of proteins and their behaviors and has become increasingly fundamental to most protein characterization studies today. In this chapter, we review the basic principles of IP and the several factors that influence each stage, and subsequently the success, of an IP experiment. Moreover, variations in application of the IP principle are discussed, and the adaptability of the techniques based on such is highlighted in the provision of two IP workflows to purify a particular protein from an entire cellular proteosome. These workflows cover the preparation and fractionation of crude cellular lysate into individual subcellular fractions, through to both "batch" and "column"-based extractions of the target protein of interest. Protocols for determining the validity of the workflows, and the presence/abundance of the protein of interest, are also briefly described.

Fluorescence study of the influence of centrifugation on graphene oxide dispersions in water and in tannic acid

Graphene oxide (GO) is acquiring a great interest in biomedicine, biotechnology and biochemistry due to its unique properties. However, GO layers are boundbyvan der Waals forces, which results in aggregation. An efficient dispersion of the aggregated nanostructures is crucial from an application viewpoint, hence eco-friendly procedures are pursued. In this work, the potential of tannic acid (TA) as a GO dispersant in water has been investigated for the first time. Transmission electronic microscopy (TEM) was used to visualize the degree of GO exfoliation in the dispersions. To further assess TA dispersant capability, a fluorescent biomolecule, riboflavin, has been selected. GO and TA cause a quenching effect on riboflavin fluorescence, which depends on the GO and TA concentration, the GO/TA weight ratio and the final centrifugation step that was found to be crucial. Multiple regression analysis has been used to determine the quenching constants for TA and GO simultaneously. The GO-riboflavin interaction weakens upon centrifugation. This step, traditionally used to remove the nanomaterial aggregates, should be avoided to obtain a high GO concentration in the dispersions. This study paves the way towards the use of environmentally friendly dispersant agents instead of conventional organic solvents or synthetic surfactants to attain high-quality dispersions of carbon nanomaterials in water.

Collection and use of porewater data from sediment bioassay studies for understanding exposure to bioavailable metals

The US Environmental Protection Agency Procedures for the Derivation of Equilibrium Partitioning Sediment Benchmarks (ESBs) for the Protection of Benthic Organisms: Metal Mixtures (Cadmium, Copper, Lead, Nickel, Silver and Zinc) equilibrium partitioning approach causally link metal concentrations and toxicological effects; they apply to sediment and porewater (i.e., interstitial water). The evaluation of bioavailable metal concentrations in porewater, using tools such as the biotic ligand model, provides an advancement that complements sediment-based evaluations. However, porewater characterization is less commonly performed in sediment bioassays than sediment chemistry characterization due to the difficulty and expense of porewater collection as well as concerns about interpretation of porewater data. This study discusses the advantages and disadvantages of different porewater extraction methods for analysis of metals and bioavailability parameters during laboratory sediment bioassays, with a focus on peepers and centrifugation. The purpose is to provide recommendations to generate bioassay porewater data of sufficient quality for use in risk-based decision-making, such as for regulated cleanup actions. Comparisons of paired data from previous bioassay studies indicate that metal porewater concentrations collected via centrifugation tend to be higher than those collected via peepers. However, centrifugation disrupts the redox status of the sediment; also, metal concentrations can vary markedly based on centrifugation conditions. Data to compare the concentrations of peeper- and centrifugation-collected bioavailability parameters (e.g., major ions, pH) are much more limited, but indicate smaller differences than those observed for metal concentrations. While peepers can be sampled without altering the redox status of the porewater, the small volume of porewater peepers collected is enough for metal concentration analysis, but insufficient for analysis of all metal bioavailability parameters. Given the benefits of metal collection via peepers, it is optimal to use centrifugation and peepers in tandem for bioassay porewater collection to improve bioavailability predictions. Environ Assess Manag 2022;18:1321-1334. © 2021 SETAC.

Modelling of Harvesting Techniques for the Evaluation of the Density of Microalgae

A better estimation of the density of cells has great relevance in the design of harvesting units. In the case of microalgae, the density is a function of the internal composition, which in turn is affected by external environmental conditions. The density of microalgae is often regarded as a constant or a generic value is retrieved from literature. This study proposes a procedure to evaluate the density of Chlorococcum sp. with simple sedimentation and centrifugation experiments coupled with the population balance equation (PBE), which is solved numerically. The density of cells is not constant; instead, it is a function of the size of particles, which in turn changes with the cells' phase of their life cycle. The calculated cellular density ranged between 1000 and 1100 kg m^-3 in function of the cell size in both the sedimentation and centrifugation tests. The method can be extended to other microalgae species as well as to other types of cells.

Role of pectin characteristics in orange juice stabilization: Effect of high-pressure processing in combination with centrifugation pretreatments

"High-pressure processing (HPP) plus" combined technologies are applied to overcome the limitation of single HPP and to produce juices with more stable quality during storage. This research explored the potential of HPP in combination with centrifugation to produce cloud stable orange juice during refrigerated storage. The results indicated that HPP combined processing technology significantly improved the cloud stability of orange juice, which was related to removed large particles, reduced viscosity, decreased protein contents, and inactivated pectin methylesterase activity induced by centrifugation (P < 0.05). Besides, chelator solubilized pectin (CSP) decreased but water solubilized pectin (WSP) maintained in the juice after centrifugation. During storage, the conversion of pectin fraction from WSP to CSP, resulting in sedimentation appeared in centrifugation treated orange juice when stored for 28 days. In general, pectin characteristics changes and pectin fractions conversion were the main driving forces affecting cloud stability of orange juice pasteurized by HPP in combination with centrifugation and during chilled storage.

[Therapeutic plasmapheresis procedures: An alternative to the disruption of the supply of polyvalent immunoglobulin in autoimmune pathologies. Medico-economic study]

INTRODUCTION

The supply of human polyvalent immunoglobulin has been under severe pressure for several years. This has led to a prioritisation of indications and a record increase in the amount of reimbursement without solving the problem of demand. Treatment by therapeutic plasmapheresis appears to be an alternative to be considered for the treatment of certain dysimmune diseseases. To discuss this alternative, we are conducting a medico-economic study comparing the polyvalent immunoglobulin strategy versus different therapeutic plasmapheresis system in the treatment of a chronic dysimmune disease.

POPULATION AND METHOD

The medico-economic study was conducted using the example of a 75 kg patient with chronic polyradiculoneuritis dependent on chronic therapy with a comparison of sequential treatment with one session of therapeutic plasmapheresis versus a course of intravenous polyvalent immunoglobulin. The medico-economic study includes an evaluation from a public health care system perspective complemented by a hospital-based approach that justifies estimating the cost of different therapeutic plasmapheresis systems based on a bottom-up micro-costing approach.

RESULTS

From the point of view of the care system, for information, a 20 g bottle of polyvalent immunoglobulin has a similar cost to a therapeutic plasmapheresis session. In our example, the cost of a maintenance treatment repeated every 2 to 4 weeks in chronic polyradiculoneuritis in a 75 kg patient is 1284.13 euros for a therapeutic plasmapheresis session versus 7331.60 to 9426.84 euros for a 1.5 to 2 mg/kg polyvalent immunoglobulin treatment. Furthermore, from the point of view of the hospital system, the cost of the different TT techniques evaluated varies moderately with the cost depending mainly on the quantity of albumin infused or the medical device used.

CONCLUSION

In the chronic sequential treatment of chronic polyradiculoneuritis, the cost of therapeutic plasmapheresis could be lower than with polyvalent immunoglobulin from a healthcare system perspective. The cost to the health care facility between different therapeutic plasmapheresis techniques differs little. This study provides arguments suggesting that if therapeutic plasmapheresis can be implemented with a dedicated technical platform, it is a serious alternative to be considered without additional costs.

A straightforward method for microplastic extraction from organic-rich freshwater samples

The extraction of microplastics from organic-rich freshwater samples is challenging and limited information is available in the literature. This study aims at developing efficient methods for water volume reduction and organic matter removal in freshwater samples, while focusing on the reduction of the economic and environmental costs, maintaining microplastics integrity and avoiding contamination. For the water volume reduction approach, centrifuging freshwater samples (water, sediment, algae, leaves, driftwood, fish tissue) at different speeds (3500, 6000 rpm) and times (5, 10 min) showed that 3500 rpm for 5 min was efficient to settle the mineral and organic material, while preserving the polymers and showing high microplastic recovering rates (93 ± 6%). These recovery rates were significantly higher than the traditional sieving approach (77 ± 22%). The posterior minimal consumption of reagents resulting from the reduction of water volume helped to reduce the economic and environmental costs of the devised methodology, becoming more aligned with green chemistry principles. For biogenic organic matter removal, four digestion solutions were tested on freshwater samples, namely 10% potassium hydroxide, Fenton reagent (30% H₂O₂ + Fe(II)), 7% and 10% sodium hypochlorite (NaClO), under 3 periods of time (1, 6 and 15 h), at 50 °C. Both 7% and 10% NaClO showed the highest rates of organic matter removal (86 ± 1% and 90 ± 1%, respectively), after 6 h at 50 °C. Exposure of virgin and aged polymers (polyethylene, polypropylene, polystyrene, polyvinyl chloride, nylon, polyethylene terephthalate) to NaClO showed no weight, visual, surface structure, Fourier transform infrared spectra and carbonyl index changes, except for nylon, although not to an extent that affected its identification. This method resulted in high recovery rates of polymers (92 ± 6%). Thus, 7% NaClO at 50 °C for 6 h (or overnight) may be efficiently used for microplastic analysis in organic-rich freshwater samples.

Effects of Different Centrifugation Protocols on the Detection of EGFR Mutations in Plasma Cell-Free DNA

Objectives

Various preanalytical factors, including the collection tube, storage conditions, and centrifugation, affect the detection results of plasma cell-free DNA (cfDNA). We compared the effect of different centrifugation protocols on the detection of EGFR mutations in cfDNA.

Methods

We analyzed 117 plasma specimens from 110 patients with non–small cell lung cancer using the cobas EGFR Mutation Test v2 (Roche Diagnostics). We compared the identified EGFR mutations and semiquantitative index values from the 1- and 2-step centrifugation groups and confirmed the clinical impact of differences in the results after further high-speed centrifugation.

Results

We detected EGFR mutations in 44 (37.6%) and 47 (40.2%) samples that were centrifuged once and twice, respectively; the 2 groups showed an 89.7% (105/117) concordance and a strong correlation in their semiquantitative index values (r = 0.929). Among the 12 inconsistent result pairs, 9 samples of 2-step centrifugation (75%) were consistent with the results of a recent tissue biopsy.

Conclusions

Additional high-speed centrifugation has been shown to increase the sensitivity of EGFR mutation detection in a commercial in vitro diagnostic real-time polymerase chain reaction device and is an optimal preanalytical factor for detecting low-allele frequency gene mutations using low concentrations of cfDNA.

Efficacy of Platelet-Rich Plasma in the treatment of a knee osteoarthritis patient with myelodysplastic syndrome

This case highlights the efficacy of plateletrich plasma (PRP) injection into patient with knee osteoarthritis (KOA) who was highly suspected to also have myelodysplastic syndrome (MDS). We discuss the possible reasons behind the therapeutic effect. KOA patients with MDS should only be administered PRP therapy carefully.

Examining the role of salinity on the dynamic stability of Pickering emulsions

HYPOTHESIS

The effect of salinity on Pickering emulsion stability to coalescence under dynamic forces present during flow in porous media for applications including enhanced oil recovery is poorly understood. Recent work suggests the absence of significant electrostatic repulsion in brine prompts unattached particles to assemble into inter-droplet networks that increase emulsion stability. We hypothesize that emulsions stabilized by nanoparticles coated with (3-glycidyloxypropyl)trimethoxysilane (GLYMO) will generate particle networks in brine and exhibit greater stability to coalescence than in deionized water (DI).

EXPERIMENTS

We stabilized decane-in-water emulsions with GLYMO-coated silica nanoparticles at various particle concentrations using brine and DI as the aqueous phase. We imaged the emulsions to calculate droplet diameters, then centrifuged the emulsions and weighed the volume of decane released to determine the extent of coalescence. We compared these measurements to evaluate the effect of salinity on emulsion stability.

FINDINGS

Emulsions demonstrate greater dynamic stability and smaller droplet diameters with increasing nanoparticle concentration and salinity. Controlling for differences in droplet size, we observe that brine reduces the emulsion coalescence rate by a factor of 78 ± 23 relative to DI. This difference supports and quantifies past work suggesting that unattached nanoparticles aggregate in brine and increase overall emulsion stability, whereas nanoparticles in DI remain separated.

Isolation of Synaptic Vesicles from Mammalian Brain

Synaptic vesicles (SVs) store neurotransmitters and undergo a fine-tuned regulatory and dynamic cycle of exo- and endocytosis, which is essential for neurotransmission at chemical synapses. The development of protocols for isolating SVs from biological extracts was a fundamental accomplishment since it allowed for characterizing the molecular properties of SVs using biochemical methods. In this chapter, we describe a modified procedure for isolating SVs from a few g of rodent brain and that can be completed within ~12 h. The protocol involves the preparation of isolated nerve terminals from which SVs are released by osmotic shock and then enriched via various centrifugation steps, followed by size exclusion chromatography as final purification step. The final vesicle fraction is 22-fold enriched in SVs over the starting material, and the final yield of SVs obtained using this protocol is approximately 20 μg of protein per gram of mouse brain. The degree of contamination by other organelles and particles monitored by morphology and immunolabeling compares well with that of the classical protocols.

Evaluation of mechanical properties of platelet-rich fibrin membrane for implant surgery: An analysis in vitro

The aim of this study was to evaluate and compare the mechanical resistance of platelet-rich fibrin (PRF) membrane when submitted to resistance traction on longitudinal axis. Blood collection of a healthy individual was collected with an amount of 300 mL and divided into 30 tubes containing 10 mL each one. The samples were divided into three groups, according to the g-force protocols: (1) F200 g: (2) F400 g; (3) F800 g. Membranes of each g-force group were divided into subgroups, according to waiting time after centrifugation: (T0) immediate use and (T30) use after 30 min. Considering these intervals of time, the concentrate was removed from tubes and inserted in a PRF metallic box to confection of the membrane. The PRF membranes were submitted to mechanical tension on a universal testing machine and obtained to a resistance force of each membrane. The centrifugation time showed no statistically significant difference for membrane resistance for any force applied (P > 0.05; Student's t-test). For T0 group results demonstrated no influence for membrane resistance (P = 0.357; Student's t-test), therefore T30 showed statistically significant difference (P = 0.040; Student's t-test) for membrane resistance for centrifugation forces applied, with highest value when applied greatest force. The findings suggest that the waiting time for centrifugation could be determined according to demand of application, and for immediate use of the membrane, the centrifugation did not influence the resistance, on the other hand, after 30 min, the application of higher force resulted in a membrane with considerable resistance.

Generation of Membrane-Derived Nanovesicles by Nitrogen Cavitation for Drug Targeting Delivery and Immunization

Extracellular vesicles (EVs) derived from cell membranes act as therapeutics and targeted drug carriers. However, the production scalability and reproducibility of EVs limit their biomedical applications. In the past few years, our lab has developed a nitrogen cavitation approach to efficiently produce EVs from any types of eukaryotic cells and bacteria. We have demonstrated that EVs derived from differentiated HL-60 cells can improve the treatment of inflammatory diseases. In addition, we have showed an increased survival of animals from bacterial infections by Pseudomonas aeruginosa after the mice were immunized with the nanovesicles derived from Pseudomonas aeruginosa membrane.

Effect of centrifugal pre-treatment on flavor change of cloudy orange juice: Interaction between pectin and aroma release

Cloud loss of orange juice could be effectively inhibited by centrifugal treatment, but it can induce flavor changes, which become a new challenge for the industry. This work aims to investigate the effect of centrifugation on flavor changes in orange juice and explore its possible mechanism. Taste- and aroma-related attributes were analyzed, and pectin was characterized. Results indicated that pH (4.00), total soluble solid (9.67 °Brix), titratable acidity (0.42%), sucrose (44%), fructose (29%), and glucose (27%) were less affected by centrifugation (P > 0.05). However, aroma compounds significantly changed (P < 0.05), where terpenes and alcohols tended to be distributed in pulp and serum after centrifugation, respectively. Pearson correlation analysis showed that aroma compound distribution induced by centrifugation was highly related to chelator-solubilized pectin fraction and sodium carbonate-solubilized pectin fraction (|R| > 0.9). In general, centrifugation clearly changed aroma of orange juice, which was mainly affected by pectin characteristics.

How centrifugation influences the recovery and soy peptone incorporation in hyaluronic acid coils from fermentation

Hyaluronic acid from fermentation (bio-HA) is a high-added-value biopolymer with a wide range of applications in aesthetic and medical areas. Bio-HA is a capsular exopolysaccharide highly hydrophilic with a coiled structure and high negative charge density at physiological pH. Centrifugation, currently used to separate microbial cells after fermentation, should significantly affect the bio-HA interactions with the medium components. Although the literature shows various centrifugation conditions for bio-HA, there is no concern about its recovery and characterization. We examined how centrifugation influences its recovery and characterized interactions with soy peptone (SP), used as a nitrogen source. We collected experimental data according to a statistical central composite design (CCD) planning with replicates at the central point with time (8-22 min) and spin (582xg to 12,402xg) as independent variables. The obtained results show bio-HA recoveries ranged from 45 ± 0.5-100% as dosed in the supernatant. The incorporation of amino acids and peptides from SP increased HA coils' density, causing losses due to sedimentation at higher spins and times. Furthermore, SP incorporation also changed the coils' size regarding HA standards of molar mass 10⁶,10⁵ and 10⁴ Da. We conclude centrifugation should significantly impact downstream processing and the total cost of bio-HA production.

Centrifugal force assessment in ram sperm: identifying species-specific impact

Background

Centrifugation is routinely employed in handling the ejaculates of some species, but it is not part of the commonly used protocols in ram. However, the development and implementation of new assisted reproductive technologies, alternative preservation models based on washing sperm from a cellular ageing-accelerating substance such as the seminal plasma, and basic studies in spermatology is associated with the use of centrifugation. This requires a specific evaluation of the centrifugation protocols considering the species-specific relationship with the potential damage produced by this procedure. No previous studies have determined the effect of different centrifugation forces on ram sperm. Therefore, we aimed to assess the performance of three centrifugal forces (600×g, 3000×g, and 6000×g for 10 min at room temperature) and their effects on ram sperm motility and functionality.

Results

Sperm motility and functionality parameters were assessed at 0 h and after 2 h of incubation at 37 °C. As expected, a higher cell packaging degree was obtained at high centrifugation forces (P ≤ 0.0001). Cell packaging was unstable at all centrifugal forces. Thus, there was a high cell resuspension rate after less than 2 min. Regarding sperm quality, there was a change in movement pattern of 3000×g and 6000×g centrifuged sperm after 2 h of incubation at 37 °C, characterized by an increase in rapid progressive motility, linearity, straightness, and beat frequency, and a decrease in medium progressive motility, curvilinear velocity, path velocity, and head lateral amplitude. Non-significant differences were obtained among the different treatments concerning the total viability. However, we observed a significant increase (P ≤ 0.05) in the percentage of viable apoptotic sperm in the samples centrifuged at 6000×g at 0 h.

Conclusions

Centrifugal forces equal to or greater than 3000×g induced some deleterious effects in ram sperm quality, and lower forces did not provide a successful cell packaging degree.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13028-021-00609-8.

Otoconia Structure After Short- and Long-Duration Exposure to Altered Gravity

Vertebrates use weight-lending otoconia in the inner ear otolith organs to enable detection of their translation during self or imposed movements and a change in their orientation with respect to gravity. In spaceflight, otoconia are near weightless. It has been hypothesized that otoconia undergo structural remodeling after exposure to weightlessness to restore normal sensation. A structural remodeling is reasoned to occur for hypergravity but in the opposite sense. We explored these hypotheses in several strains of mice within a Biospecimen Sharing Program in separate space- and ground-based projects. Mice were housed 90 days on the International Space Station, 13 days on two Shuttle Orbiter missions, or exposed to 90 days of hindlimb unloading or net 2.38 g via centrifugation. Corresponding flight habitat and standard cage vivarium controls were used. Utricular otoliths were visually analyzed using scanning electron microscopy and in selected samples before and after focused ion beam (FIB) milling. Results suggest a possible mass addition to the otoconia outer shell might occur after exposure to longer-duration spaceflight, but not short ones or hindlimb unloading. A destructive process is clearly seen after centrifugation: an ablation or thinning of the outer shell and cavitation of the inner core. This study provides a purely descriptive account of otoconia remodeling after exposures to altered gravity. The mechanism(s) underlying these processes must be identified and quantitatively validated to develop countermeasures to altered gravity levels during exploration missions.

Scaled preparation of extracellular vesicles from conditioned media

Extracellular vesicles (EVs) especially of mesenchymal stem/stomal cells (MSCs) are increasingly considered as biotherapeutic agents for a variety of different diseases. For translating them effectively into the clinics, scalable production processes fulfilling good manufacturing practice (GMP) are needed. Like for other biotherapeutic agents, the manufacturing of EV products can be subdivided in the upstream and downstream processing and the subsequent quality control, each of them containing several unit operations. During upstream processing (USP), cells are isolated, stored (cell banking) and expanded; furthermore, EV-containing conditioned media are produced. During downstream processing (DSP), conditioned media (CM) are processed to obtain concentrated and purified EV products. CM are either stored until DSP or are directly processed. As first unit operation in DSP, clarification removes remaining cells, debris and other larger impurities. The key operations of each EV DSP is volume-reduction combined with purification of the concentrated EVs. Most of the EV preparation methods used in conventional research labs including differential centrifugation procedures are limited in their scalability. Consequently, it is a major challenge in the therapeutic EV field to identify appropriate EV concentration and purification methods allowing scale up. As EVs share several features with enveloped viruses, that are used for more than two decades in the clinics now, several principles can be adopted to EV manufacturing. Here, we introduce and discuss volume reducing and purification methods frequently used for viruses and analyze their value for the manufacturing of EV-based therapeutics.

The effect of the anticoagulant on the cellular composition and growth factor content of platelet-rich plasma

BACKGROUND

The cellular and biochemical composition of the platelet rich plasma (PRP) may impact its regenerative capacity. PRP composition have been shown to vary substantially among different separation systems and protocols. The type and the dose of anticoagulant might affect the content of PRP.

OBJECTIVE

The objective of this study was to evaluate the effect of anticoagulant use, on cellular composition and the amount of growth factors in fresh PRP.

METHODS

Three different methods were used to prepare PRP from 12 healthy participants. The protocol 1 included standart dose sodium citrate (SC) (0.9 ml, 3.8%), protocol 2 included 0.5 ml SC and no anticoagulant was used in protocol 3. The PRP's were compared in regards to cellular content, capture efficiency of platelets (CE), concentrations and total doses of fresh studied vascular endothelial growth factor (VEGF), platelet derived growth factor -BB, (PDGF-BB), transforming growth factor β1 (TGF-β1) levels.

RESULTS

The CE and total platelet count were highest in protocol 1. The white blood cells (WBC) and VEGF were highest in protocol 3. The highest total TGF-β1 and total PDGF levels were obtained with protocol 1, while the highest total VEGF levels were obtained with protocol 3.

CONCLUSION

The results of this study revealed that the use and the dose of SC affects the cellular content of PRP and GFs measured in fresh PRP. The CE and platelet dose increases while the WBC and VEGF decreases with the use of SC.

A critical review on different harvesting techniques for algal based biodiesel production

The fuels retrieved from renewable sources which are usually employed as both carbon and energy sources are termed as neutral based biofuels. The most promising feedstock from renewable sources with great potentiality in contributing to the inclining energy demand is microalgae. These microalgae can be harnessed readily in terms of obtaining qualitative biodiesel with greater energy consumption under limited operational cost. The process of harvesting or dewatering microalgae could be carried under single or sequential combinations of operations. The major drawback of harvesting such as huge operational cost could be lowered by increasing the level of automation than cost of investments. The present review concentrates and explores on the techno-economic analysis of the microalgal harvesting and dewatering processes on a large scale. Along with these advanced techniques enclosing the utilization of nanoparticles for harvesting has also been explored. And it also adds with the impacts of concerning facts on energy consumption, processing cost and recovery of resources during harvesting.

Isolation of Mitochondria-Associated ER Membranes (MAMs), Synaptic MAMs, and Glycosphingolipid Enriched Microdomains (GEMs) from Brain Tissues and Neuronal Cells

Subcellular fractionation is a valuable procedure in cell biology to separate and purify various subcellular constituents from one another, i.e., nucleus, cytosol, membranes/organelles, and cytoskeleton. The procedure relies on the use of differential centrifugation of cell and tissue homogenates. Fractionated subcellular organelles may be subjected to additional purification steps that enable the isolation of specific cellular sub-compartments, including interorganellar membrane contact sites. Here we outline a protocol tailored to the isolation of mitochondria, mitochondria-associated ER membranes (MAMs), and glycosphingolipid enriched microdomains (GEMs) from the adult mouse brain, primary neurospheres, and murine embryonic fibroblasts (MEFs). We also provide a detailed protocol for the purification of synaptosomes and their corresponding MAMs .

Harvesting freshwater algae with tannins from the bark of forest species: Comparison of methods and pelletization of the biomass obtained

Toxic cyanobacteria growth rates have increased in recent decades due to climate change and human activities. Microalgae, with their ability to produce a large amount of biomass, are considered as a source of energy that can be used to produce biofuels. The aim of this study is to test four different microalgae harvesting methods (sedimentation, coagulation-flocculation, pH variation, and centrifugation) in order to find which is best suited to the A Baxe reservoir, which has been suffering from cyanobacterial blooms in recent years. Centrifugation proved the most efficient method (85.74%-1790 RCF), but it can induce cell rupture. Natural sedimentation and pH variation obtained similar results at 49.36% and 49.02% respectively. Although all four methods have advantages, our results reveal that coagulation-flocculation, using 10 mg/L of Pinus pinaster, results in a removal efficiency of 68.10%, making it the most suitable method, though with 20 mg/L the performance was lower (66.03%). To minimise environmental waste, the microalgae removed were then transformed into pellets to be used as biofuel, with a higher heating value (HHV) of 21,196.96 ± 1602.33 kJ/kg. The pellets obtained from the microalgae residue did not meet all the requirements for use as biofuels, but microalgae biomass could be mixed with other sources and therefore looks like a promising option for the future.

Production of Zika Virus Virus-Like Particles

Zika virus (ZIKV) is a mosquito-transmitted virus that has caused major outbreaks of disease around the world over the last few years. The infectious ZIKV consists of a structural protein outer shell surrounding a nucleocapsid. Virus-like particles (VLP) consist of the outer structural protein shell, but without the nucleocapsid, and are hence noninfectious. VLP, however, are structurally equivalent to the native virus and thus present a similar antigenic profile. These properties make them good candidates for vaccine development. ZIKV VLP can be generated on a laboratory scale by cloning the relevant structural proteins into a eukaryotic expression vector and transfecting the construct into mammalian cells. The secreted VLP can be harvested from the culture medium and purified by sucrose cushion ultracentrifugation. Validation of the VLP is achieved through western blotting and electron microscopy.

Recent Progress in Harvest and Recovery Techniques of Mammalian and Algae Cells for Industries

In our modern world, biotechnology products play important roles not only in our health and culture, but also various industries such as food, agriculture, sewage treatment, biofuels, nutraceuticals, and pharmaceuticals. Rapid technological advances in biotechnology over the last few decades have allowed industrial integration of mammalian cells (like the Chinese hamster ovary cells) and algae cells in pharmaceutical and biofuel industries to produce commercial products and valuable biomolecules. However, the cost of cell harvest and recovery can become expensive depending on the harvesting technique, degree of purification, and intended use of the end-products. This has led to numerous research in exploring and developing efficient harvesting techniques. Therefore, in this review, the popular harvesting techniques and their recent applications will be discussed.

A novel method for extraction of polypropylene microplastics in swine manure

With the development of modern industry and agriculture, plentiful microplastics (MPs) were produced as a result of the abuse of plastic. The widespread presence of MPs in soils has caused coastal ecological environment pollution. Previous research has shown that fertilizer is one pathway for the entry of MPs into agricultural soils. Meanwhile, livestock manure is a major fertilizer for crops, and the application of livestock manure compost creates a potential pathway for MPs to enter soils. Thus, MPs may exist in livestock manure from the process of livestock breeding and ultimately contaminate agricultural soils. Based on the increasing attention to MP pollution, manure-born MPs will attract more interest in the future. Thus, the present study compares the extraction effects of centrifugation with fractional distillation, and an improved method is introduced to extract polypropylene (PP) from different types of swine manure. The numbers of particles and fibers were determined using a camera (MS60) connected to a stereomicroscope (Mshot MZ62), and the results showed that the recovery rate of plastic particles in swine manure based on different added numbers ranged from 71.43% ± 8.36 to 96.67% ± 3.33 with the centrifugation method, and only 31.11% ± 10.56 to 43.33% ± 12.56 using fractional distilling. The recovery rate for fibers was generally higher than for particles, especially using centrifugation, and ranged from 95.67% ± 1.58 to 100% ± 0, while the rate of fiber recovery using fractional distillation ranged from 39.44% ± 10.66 to 39.44 ± 10.66. The results of recovery rates using the two methods show that the effect of extraction by centrifugation is superior to the method of fractional distillation, with a recovery rate of approximately 100% for fibers and 90% for particles. The recovery number of microplastics evaluated with a line regression model was acceptable. Graphical abstract.

Switchgrass as oil and water-spill sorbent: Effect of particle size, torrefaction, and regeneration methods

Switchgrass, both raw and torrefied, was tested for its ability to sorb water or oil. The cyclic performance was also examined, utilizing centrifugal extraction as the regeneration method. Both oil and water sorption capacity increase with the decreasing size of raw switchgrass particles. Results indicate that 3 mm raw switchgrass can sorb water at a capacity of about 6 times its mass and can sorb oil at a capacity of about 3 times its mass, which makes it a suitable biodegradable sorbent. Torrefaction at 220 °C for 30 min reduces water sorption capacity by an average of 55% but does not have a statistically significant impact on oil sorption. Sorption of liquid is negatively correlated to particle size. Centrifugation is able to partially desorb either liquid from the sorbent, and subsequent sorption cycles do not display lower sorption capacity than the first cycle when calculated on a dry mass basis.