Multiple Targeted Drugs Carrying Biodegradable Membrane Barrier: Anti-Adhesion, Hemostasis, and Anti-Infection

Nanotechnology in Cancer Diagnosis and Treatment

Traditional cancer diagnosis has been aided by the application of nanoparticles (NPs), which have made the process easier and faster. NPs possess exceptional properties such as a larger surface area, higher volume proportion, and better targeting capabilities. Additionally, their low toxic effect on healthy cells enhances their bioavailability and t-half by allowing them to functionally penetrate the fenestration of epithelium and tissues. These particles have attracted attention in multidisciplinary areas, making them the most promising materials in many biomedical applications, especially in the treatment and diagnosis of various diseases. Today, many drugs are presented or coated with nanoparticles for the direct targeting of tumors or diseased organs without harming normal tissues/cells. Many types of nanoparticles, such as metallic, magnetic, polymeric, metal oxide, quantum dots, graphene, fullerene, liposomes, carbon nanotubes, and dendrimers, have potential applications in cancer treatment and diagnosis. In many studies, nanoparticles have been reported to show intrinsic anticancer activity due to their antioxidant action and cause an inhibitory effect on the growth of tumors. Moreover, nanoparticles can facilitate the controlled release of drugs and increase drug release efficiency with fewer side effects. Nanomaterials such as microbubbles are used as molecular imaging agents for ultrasound imaging. This review discusses the various types of nanoparticles that are commonly used in cancer diagnosis and treatment.

Dual drug-loaded PLGA fibrous scaffolds for effective treatment of breast cancer in situ

Advanced metastatic breast cancer remains nearly an incurable disease. In situ therapy may help patients with worse prognoses have better clinical outcomes by significantly reducing systematic toxicity. Dural-drug fibrous scaffold was created and assessed using an in-situ therapeutic strategy, simulating the preferred regimens advised by the National Comprehensive Cancer Network. DOX, a once-used chemotherapy drug is embedded into scaffolds and produces a fast release for two cycles to kill tumor cells. PTX, a hydrophobic drug is continuously injected and produces a gradual release for up to two cycles to treat long cycles. Chosen drug loading system and the designated fabrication parameter controlled the releasing profile. Drug carrier system complied with the clinical regimen. It demonstrated both in vitro and in vivo anti-proliferative effects on the breast cancer model. The dosage of an intratumoral injection to drug capsules, the local tissue toxicity could be significantly reduced. To optimized intravenous injection with dual drugs, fewer side effects and a higher survival rate were seen even in the large tumor model (450-550 mm³). Drug delivery system makes the precise accumulation of the topical drug concentration possible, simulating clinically successful therapy and possibly offering better clinical treatment options for solid tumors.

Mechanisms Affecting Physical Aging and Swelling by Blending an Amphiphilic Component

Polymer blending is a promising method to overcome stability obstacles induced by physical aging and swelling of implant scaffolds prepared from amorphous polymers in biomedical application, since it will not bring potential toxicity compared with chemical modification. However, the mechanism of polymer blending still remains unclearly explained in existing studies that fail to provide theoretical references in material R&D processes for stability improvement of the scaffold during ethylene oxide (EtO) sterilization, long-term storage, and clinical application. In this study, amphiphilic poly(ethylene glycol)-co-poly(lactic acid) (PELA) was blended with amorphous poly(lactic-co-glycolic acid) (PLGA) because of its good miscibility so as to adjust the glass transition temperature (Tg) and hydrophilicity of electrospun PLGA membranes. By characterizing the morphological stability and mechanical performance, the chain movement and the glass transition behavior of the polymer during the physical aging and swelling process were studied. This study revealed the modification mechanism of polymer blending at the molecular chain level, which will contribute to stability improvement and performance adjustment of implant scaffolds in biomedical application.

Alpha-terpineol grafted acetylated lentinan as an anti-bacterial adhesion agent

Biomedical implants-associated bacterial infections have become a major threat to human health. Therefore, it is meaningful to develop new antibacterial strategies to solve this problem. In this study, we conjugated acetylated lentinan (AceLNT) with α-terpineol (AceLNT-g-α-ter), a highly effective natural antibacterial compound, to constitute a novel AceLNT-g-α-ter membrane (AceLNT-g-α-terM). Compared with AceLNT membrane (AceLNTM), the adhesion amount of E. coli and P. aeruginosa in AceLNT-g-α-terM decreased by 80% and 85% after 7 d incubation in fluid bacterial medium. Moreover, the number of E. coli and P. aeruginosa biofilm on AceLNT-g-α-terM surface decreased by 70% and 71%. At the meanwhile, α-terpineol grafting modification of AceLNT had limited effect on its stimulating activity on macrophages and had no more cytotoxicity. In summary, our study firstly confirmed that AceLNT-g-α-terM could effectively inhibit gram-negative bacteria adhesion and biofilm formation, and provided a novel strategy for preventing infection of biomedical implants.

Prevention of Post-Operative Adhesions: A Comprehensive Review of Present and Emerging Strategies

Post-operative adhesions affect patients undergoing all types of surgeries. They are associated with serious complications, including higher risk of morbidity and mortality. Given increased hospitalization, longer operative times, and longer length of hospital stay, post-surgical adhesions also pose a great financial burden. Although our knowledge of some of the underlying mechanisms driving adhesion formation has significantly improved over the past two decades, literature has yet to fully explain the pathogenesis and etiology of post-surgical adhesions. As a result, finding an ideal preventative strategy and leveraging appropriate tissue engineering strategies has proven to be difficult. Different products have been developed and enjoyed various levels of success along the translational tissue engineering research spectrum, but their clinical translation has been limited. Herein, we comprehensively review the agents and products that have been developed to mitigate post-operative adhesion formation. We also assess emerging strategies that aid in facilitating precision and personalized medicine to improve outcomes for patients and our healthcare system.

A review: progress in preventing tissue adhesions from a biomaterial perspective

Postoperative adhesions (POA) are one of the main problems suffered by patients and are a common complaint. It is considered to be closely associated with the healing mechanism of damaged tissues. Tissue adhesions accompany other symptoms such as inflammation, pain, and even dyskinesia under certain conditions, compromising the patients' quality of life. On the other hand, common treatments involve high costs, re-surgery or long-term hospital stays. Therefore, alternative approaches need to be formulated so that aforementioned problems can be resolved. To this end, a review of recent advances in this context is imperative. In this review, we have highlighted the mechanism of adhesion formation, advances in common therapeutic approaches, and prospective treatments in preventing tissue adhesions. Based on the literature, it can be determined that the disadvantages of available commercial products in the treatment of tissue adhesion have led researchers to utilize alternative methods for designing anti-adhesive products with different structures such as electrospun fibrous mats, hydrogels, and nanospheres. These studies are on the fast track in producing optimal anti-adhesion materials. We hope that this article can attract attention by showing various mechanisms and solutions involved in adhesion problems and inspire the further development of anti-adhesion biomaterials.

Controlled drug release: On the evolution of physically entrapped drug inside the electrospun poly(lactic-co-glycolic acid) matrix

The drug loading and releasing properties of poly(lactic-co-glycolic acid) (PLGA) were approached with the application of neutron techniques. The neutron reflection (NR) study on the response of PLGA material to vapor and to bulk water revealed that the hydration of PLGA origins from the molecular compatibility between water and PLGA. Hydration is reversible with regard to the change in humidity and temperature. Capecitabine as drug was embedded in the electrospun PLGA fibers. Small angle neutron scattering (SANS) was able to disclose the domain of entrapped drug inside the fibers and trace its evolution over time when the electrospun membrane was incubated in D₂O buffer solution. The evolution of drug domains is discussed in terms of the concentration dependence, the temperature dependence, and the relevance between the drug diffusion inside the polymer matrix and the drug release out to the medium. It was observed that, at 20 °C the drug-related domains are relatively small (~ 100 Å) and relax extremely slow while at 37 °C the drug-related domains are relatively larger (~ 200 Å) and relax faster. These behaviors can be related to the glassy property of structural material. The transportation of drug through the polymer matrix relies on the global relaxation of PLGA chains. The variation of fiber diameter vs. incubation time was followed by ultra-small angle neutron scattering (USANS). The bi-phasic or tri-phasic release kinetics from a series of fibers with different drug loading (2%, 5%, 10%, 20%, 30%, 40%, 50%) were discussed based on the SANS and USANS discovery.

Antimicrobial effects of positively charged, conductive electrospun polymer fibers

In recent years, electrospun polymer fibers have gained attention for various antibacterial applications. In this work, the effect of positively charged polymer fiber mats as antibacterial gauze is studied using electrospun poly(caprolactone) and polyaniline nanofibers. Chloroxylenol, an established anti-microbial agent is used for the first time as a secondary dopant to polyaniline during the electrospinning process to make the surface of the polyaniline fiber positively charged. Both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli are used to investigate the antibacterial activity of the positively charged and uncharged polymer surfaces. The results surprisingly show that the polyaniline surface can inhibit the growth of both bacteria even when chloroxylenol is used below its minimum inhibitory concentration. This study provides new insights allowing the better understanding of dopant-based, intrinsically conducting polymer surfaces for use as antibacterial fiber mats.

A synergistic bactericidal effect of low-frequency and low-intensity ultrasound combined with levofloxacin-loaded PLGA nanoparticles on M. smegmatis in macrophages

Purpose

Tuberculosis (TB) is a highly infectious disease caused by Mycobacterium tuberculosis (Mtb), which often parasites in macrophages. This study is performed to investigate the bactericidal effect and underlying mechanisms of low-frequency and low-intensity ultrasound (LFLIU) combined with levofloxacin-loaded PLGA nanoparticles (LEV-NPs) on M. smegmatis (a surrogate of Mtb) in macrophages.

Methods and results

The LEV-NPs were prepared using a double emulsification method. The average diameter, zeta potential, polydispersity index, morphology, and drug release efficiency in vitro of the LEV-NPs were investigated. M. smegmatis in macrophages was treated using the LEV-NPs combined with 42 kHz ultrasound irradiation at an intensity of 0.13 W/cm² for 10 min. The results showed that ultrasound significantly promoted the phagocytosis of nanoparticles by macrophages (P < 0.05). In addition, further ultrasound combined with the LEV-NPs promoted the production of reactive oxygen species (ROS) in macrophage, and the apoptosis rate of the macrophages was significantly higher than that of the control (P < 0.05). The transmission electronic microscope showed that the cell wall of M. smegmatis was ruptured, the cell structure was incomplete, and the bacteria received severe damage in the ultrasound combined with the LEV-NPs group. Activity assays showed that ultrasound combined with the LEV-NPs exhibited a tenfold higher antibacterial activity against M. smegmatis residing inside macrophages compared with the free drug.

Conclusion

These data demonstrated that ultrasound combined with LEV-NPs has great potential as a therapeutic agent for TB.

Mechanism of a long-term controlled drug release system based on simple blended electrospun fibers

BACKGROUND

Drug delivery systems based on electrospun fibers have been under development for many years. However, studies of controllable long-term drug release from electrospun membrane systems and the underlying release mechanisms have seldom been reported.

METHODS

In this study, electrospun membrane drug delivery systems consisting of the antibiotic ciprofloxacin hydrochloride and FDA-approved polymers are fabricated. Different second-component polymers are introduced to change the properties of a poly(d,l-lactide-co-glycolide) (PLGA) matrix, thereby altering the drug release behavior. On the basis of observations of morphology, cumulative release profiles, and determinations of release duration, the drug release kinetics and critical characteristics influencing drug release behavior are discussed.

RESULTS

It is found that the drug release profiles can be divided into three stages according to the rate of drug release. Stage I is controlled by fiber swelling and diffusion according to Fick's second law. Stage II is controlled by diffusion through a fused membrane structure, which results in very slow drug release. Stage III is controlled by polymer degradation and involves release of the remaining drug.

CONCLUSIONS

The results of this study of release mechanisms should provide a basis for adjustments of drug release dosage and duration, thereby contributing to the development of drug delivery systems satisfying clinical requirements.

Recent Advances in Hemostasis at the Nanoscale

Rapid and effective hemostatic materials have received wide attention not only in the battlefield but also in hospitals and clinics. Traditional hemostasis relies on materials with little designability which has many limitations. Nanohemostasis has been proposed since the use of peptides in hemostasis. Nanomaterials exhibit excellent adhesion, versatility, and designability compared to traditional materials, laying a good foundation for future hemostatic materials. This review first summarizes current hemostatic methods and materials, and then introduces several cutting-edge designs and applications of nanohemostatic materials such as polypeptide assembly, electrospinning of cyanoacrylate, and nanochitosan. Particularly, their advantages and working mechanisms are introduced. Finally, the challenges and prospects of nanohemostasis are discussed.

Evaluation of absorbable hemostatic agents of polyelectrolyte complexes using carboxymethyl starch and chitosan oligosaccharide both in vitro and in vivo

CMS/COS PECs with a suitable COS content were promising absorbable hemostatic agents for internal use.

Evaluation of a series of silk fibroin protein-based nonwoven mats for use as an anti-adhesion patch for wound management in robotic surgery

A novel anti-adhesion nonwoven mat mainly composed of silk fibroin protein (SFP) was fabricated via the single-spinneret electrospinning technique. A series of SFP-based electrospun nonwoven mats containing additives of different synthetic polymer ratios, such as pure SFP, SFP/poly(vinyl alcohol) (PVA), SFP/polyethylene glycol (PEG), and SFP/polyethylene oxide (PEO) were produced and compared. All membranes were porous and had diameters of 324.02 ± 113.7, 308.86 ± 74.02, 366.22 ± 115.81, and 341.82 ± 119.42 nm, respectively. The average pore size for each membrane was 1.132 ± 0.99, 0.811 ± 0.424, 0.975 ± 0.741, and 0.784 ± 0.497 μm² . No nonwoven mats showed significant cytotoxicity toward fibroblast cells based on the results of MTT assays. Surprisingly, for all groups of SFP-based nonwoven mats, nitrate formation was reduced by up to 94.55 ± 14.50%, 92.16 ± 19.38%, 91.28 ± 28.375%, and 92.00 ± 12.64% in lipopolysaccharide-induced RAW 264.7 macrophages model. Tissue anti-adhesion potential was evaluated in an in vitro fibroblast cell adhesion model and in vivo wounded mice model. In vitro, the mean cell anti-adhesion percentage of fibroblast cells changed over time in the following order: PVA/SFP > SFP > PEG/SFP∼PEO/SFP. In vivo, SFP and PVA/SFP-treated groups both showed superior collagen regeneration and wound closure. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 221-230, 2018.

Polymer materials for prevention of postoperative adhesion

Postoperative adhesion (POA) is a common complication that often occurs after a variety of surgeries, such as plastic surgery, repair operations of abdominal, pelvic, and tendon, and so forth. Moreover, POA leads to chronic abdominal pain, secondary infertility in women, intestinal obstruction, and other severe complications, which significantly reduce the life quality of patients. In order to prevent the formation of POA, a number of strategies have been developed, among which an emerging method is physical barriers consisting of polymer materials. This review highlights the most commonly used natural and synthetic polymer materials in anti-adhesion physical barriers. The specific features of polymer materials are analyzed and compared, and the possible prospect is also predicted.

STATEMENT OF SIGNIFICANCE

Postoperative adhesion (POA) is a serious complication accompanied with various surgeries. Polymer material-based physical barriers have attracted a large amount of attention in POA prevention. The polymer barriers can effectively avoid the formation of fibrous tissues among normal organs by reducing the interconnection of injured tissues. In this review, specific features of the natural and synthetic polymer materials for application in POA prevention were presented, and the possible prospects were predicted. All in all, our work can provide inspiration for researchers to choose proper polymer materials for preclinical and even clinical anti-adhesion studies.

Electrospun nanofibers for wound healing

Electrospinning has been widely used as a nanofiber fabrication technique. Its simple process, cost effectiveness and versatility have appealed to materials scientists globally. Pristine polymeric nanofibers or composite nanofibers with dissimilar morphologies and multidimensional assemblies ranging from one dimension (1D) to three dimensions (3D) can be obtained from electrospinning. Critically, these as-prepared nanofibers possessing high surface area to volume ratio, tunable porosity and facile surface functionalization present numerous possibilities for applications, particularly in biomedical field. This review gives us an overview of some recent advances of electrospinning-based nanomaterials in biomedical applications such as antibacterial mats, patches for rapid hemostasis, wound dressings, drug delivery systems, as well as tissue engineering. We further highlight the current challenges and future perspectives of electrospinning-based nanomaterials in the field of biomedicine.

A self-defensive antibacterial coating acting through the bacteria-triggered release of a hydrophobic antibiotic from layer-by-layer films

Drug delivery systems play important roles in the construction of antibacterial coatings on the surfaces of biomaterials. However, excessive release of antibiotics in the environment can lead to the generation of resistant bacteria. A methoxy poly(ethylene glycol)-poly(ε-caprolactone)-chitosan (MPEG-PCL-CS) block polymer was prepared through covalent grafting of CS onto MPEG-PCL. MPEG-PCL-CS micelles were prepared and showed a high load capacity for the hydrophobic antibiotic triclosan (TCA) (∼5 wt%). Multilayer films were constructed through self-assembling TCA/MPEG-PCL-CS cationic micelles with poly(acrylic acid) (PAA). Transmission and scanning electron microscopy analyses confirmed the presence of micelles on the surface (20-40 nm). As barriers for the antibiotic, the (TCA/MPEG-PCL-CS)/PAA multilayer films contained a high load of TCA (255 μg cm-2). Importantly, the multilayer films showed both bacteria-triggered and pH-responsive release properties and can be used as self-defensive antibacterial coatings. Bacterial adhesion caused a local acidic environment and altered the permeability of the multilayer films, promoting drug release. Both in vitro and in vivo antibacterial tests indicated a high bactericidal activity of drug-loaded multilayer films against both E. coli and S. aureus.

Fabrication of curcumin-loaded mesoporous silica incorporated polyvinyl pyrrolidone nanofibers for rapid hemostasis and antibacterial treatment

A new hemostasis material composed of curcumin-loaded mesoporous silica and polyvinyl pyrrolidone nanofibers with rapid hemostasis and antibacterial ability.

Dual crosslinked hyaluronic acid nanofibrous membranes for prolonged prevention of post-surgical peritoneal adhesion

A HA NFM crosslinked with FeCl₃and BDDE shows prolonged degradation to prevent peritoneal adhesion.

Antibacterial and hemostatic composite gauze of N,O-carboxymethyl chitosan/oxidized regenerated cellulose

Viscose gauze was oxidized with NO₂/CCl₄ to prepare Oxidized Regenerated Cellulose (ORC).

Controlled Antibiotics Release System through Simple Blended Electrospun Fibers for Sustained Antibacterial Effects

Implantation of sustained antibacterial system after abdominal surgery could effectively prevent complicated intra-abdominal infection. In this study, a simple blended electrospun membrane made of poly(D,L-lactic-co-glycolide) (PLGA)/poly(dioxanone) (PDO)/Ciprofloxacin hydrochloride (CiH) could easily result in approximately linear drug release profile and sustained antibacterial activity against both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The addition of PDO changed the stack structure of PLGA, which in turn influenced the fiber swelling and created drug diffusion channels. It could be a good candidate for reducing postoperative infection or be associated with other implant to resist biofilm formation.

Therapeutic application of electrospun nanofibrous meshes

Fabricating tissue architecture-mimicking scaffolds is one of the major challenges in the field of tissue engineering. Electrospun nanofibers have been considered as potent techniques for fabricating fibrous scaffolds biomimicking extracellular frameworks. Therapeutic agent-incorporated nanofibrous meshes have widely served as excellent substrates for adhesion, proliferation and differentiation. Many drugs, proteins and nucleic acids were incorporated into the scaffolds for regeneration of skin, musculoskeletal, neural and vascular tissue engineering in aims to control the release of the therapeutic agents. In the current article, we focus on introducing various fabrication techniques for electrospun nanofiber-based scaffolds and subsequent functionalization of nanofibers for therapeutic purposes. We also detail how the therapeutic nanofibrous meshes can be employed in the field of tissue engineering.

Gold nanorod-embedded electrospun fibrous membrane as a photothermal therapy platform

A strategy of using a gold nanorod (GNR)-loaded electrospun membrane as a photothermal therapy platform of cancer is reported. The strategy takes both the advantages of the excellent photothermal properties of GNRs to selectively kill the cancerous cells, and the widely used biodegradable electrospun membrane to serve as GNR-carrier and surgical recovery material. PEG modified GNRs were embedded into the electrospun fibrous membrane which was composed of PLGA and PLA-b-PEG with an 85:15 ratio. After incubation with the cells in the cell culture medium, the PEG-GNRs were released from the membrane and taken up by cancer cells, allowing the generation of heat upon NIR irradiation to induce cancer cell death. We have demonstrated that the use of PEG-GNR-embedded membrane selectively killed the cancerous cells and effectively inhibited cancer cell proliferation though in vitro experiments. The PEG-GNRs-loaded membrane is a promising material for postsurgical recovery of cancer.

Preparation and optimization of silver nanoparticles embedded electrospun membrane for implant associated infections prevention

A strategy of using silver nanoparticle (AgNP)-loaded electrospun membrane as a novel coating material for preventing implant associated infections is reported. The strategy takes both the advantages of the excellent antibacterial as well as no drug resistance properties of AgNPs, and the widely used biodegradable electrospun membrane to serve as AgNP carrier and physical obstruction of bacteria adhesion. However, AgNPs have not been applied in clinical treatment yet because the concern of the potential toxicity. For the first time, we systematically investigated toxicity of AgNP-based coating materials in vitro and in vivo. Three dosages (0.1, 0.5, and 1.0 wt %) of silver nanoparticles (AgNPs) were embedded in biodegradable PLGA electrospun membranes as treatment devices to determine the precise concentration of AgNPs, minimize the dosage, and consequently reduced the toxicity in clinical applications. On the basis of antibacterial results and toxicity evaluations, PLGA electrospun membranes containing 0.5 wt % of AgNPs was considered as the most suitable combination, which is safe and effective for clinical application.