Bovine Serum Albumin (BSA)/polyacrylonitrile (PAN) biohybrid nanofibers coated with a biomineralized calcium deficient hydroxyapatite (HA) shell for wound dressing

Preparation of pH-sensitive porous polylactic acid-based medical dressing with self-pumping function

Excessive exudation from the wound site and the difficulty of determining the state of wound healing can make medical management more difficult and, in extreme cases, lead to wound deterioration. In this study, we fabricated a pH-sensitive colorimetric chronic wound dressing with self-pumping function using electrostatic spinning technology. It consisted of three layers: a polylactic acid-curcumin (PCPLLA) hydrophobic layer, a hydrolyzed polyacrylonitrile (HPAN) transfer layer, and a polyacrylonitrile-purple kale anthocyanin (PAN-PCA) hydrophilic layer. The results showed that the preparation of porous PLLA fiber membrane loaded with 0.2 % Cur was achieved by adjusting the spinning-related parameters, which could ensure that the composite dressing had sufficient anti-inflammatory, antibacterial and antioxidant properties. The HPAN membrane treated with alkali for 30 min had significantly enhanced liquid wetting ability, and the unidirectional transport of liquid could be achieved by simple combination with the 20 um PCPLLA fiber membrane. In addition, the 4 % loaded PCA showed more obvious color difference than the colorimetric membrane. In vivo and ex vivo experiments have demonstrated the potential of multifunctional dressings for the treatment of chronic wounds.

Nanofibrous polyelectrolyte complex incorporated BSA-alginate composite bioink for 3D bioprinting of bone mimicking constructs

Although several bioinks have been developed for 3D bioprinting applications, the lack of optimal printability, mechanical properties, and adequate cell response has limited their practical applicability. Therefore, this work reports the development of a composite bioink consisting of bovine serum albumin (BSA), alginate, and self-assembled nanofibrous polyelectrolyte complex aggregates of gelatin and chitosan (PEC-GC). The nanofibrous PEC-GC aggregates were prepared and incorporated into the bioink in varying concentrations (0 % to 3 %). The bioink samples were bioprinted and crosslinked post-printing by calcium chloride. The average nanofiber diameter of PEC-GC was 62 ± 15 nm. It was demonstrated that PEC-GC improves the printability and cellular adhesion of the developed bioink and modulates the swelling ratio, degradation rate, and mechanical properties of the fabricated scaffold. The in vitro results revealed that the bioink with 2 % PEC-GC had the best post-printing cell viability of the encapsulated MG63 osteosarcoma cells and well oragnized stress fibers, indicating enhanced cell adhesion. The cell viability was >90 %, as observed from the MTT assay. The composite bioink also showed osteogenic potential, as confirmed by the estimation of alkaline phosphatase activity and collagen synthesis assay. This study successfully fabricated a high-shape fidelity bioink with potential in bone tissue engineering.

Tunable electrospun scaffolds of polyacrylonitrile loaded with carbon nanotubes: from synthesis to biological applications

Growing cells in a biomimetic environment is critical for tissue engineering as well as for studying the cell biology underlying disease mechanisms. To this aim a range of 3D matrices have been developed, from hydrogels to decellularized matrices. They need to mimic the extracellular matrix to ensure the optimal growth and function of cells. Electrospinning has gained in popularity due to its capacity to individually tune chemistry and mechanical properties and as such influence cell attachment, differentiation or maturation. Polyacrylonitrile (PAN) derived electrospun fibres scaffolds have shown exciting potential due to reports of mechanical tunability and biocompatibility. Building on previous work we fabricate here a range of PAN fibre scaffolds with different concentrations of carbon nanotubes. We characterize them in-depth in respect to their structure, surface chemistry and mechanical properties, using scanning electron microscopy, image processing, ultramicrotomic transmission electron microscopy, x-ray nanotomography, infrared spectroscopy, atomic force microscopy and nanoindentation. Together the data demonstrate this approach to enable finetuning the mechanical properties, while keeping the structure and chemistry unaltered and hence offering ideal properties for comparative studies of the cellular mechanobiology. Finally, we confirm the biocompatibility of the scaffolds using primary rat cardiomyocytes, vascular smooth muscle (A7r5) and myoblast (C2C12) cell lines.

Levofloxacin loaded poly (ethylene oxide)-chitosan/quercetin loaded poly (D,L-lactide-co-glycolide) core-shell electrospun nanofibers for burn wound healing

This study developed a new burn wound dressing based on core-shell nanofibers that co-deliver antibiotic and antioxidant drugs. For this purpose, poly(ethylene oxide) (PEO)-chitosan (CS)/poly(D,L-lactide-co-glycolide) (PLGA) core-shell nanofibers were fabricated through co-axial electrospinning technique. Antibiotic levofloxacin (LEV) and antioxidant quercetin (QS) were incorporated into the core and shell parts of PEO-CS/PLGA nanofibers, respectively. The drugs could bond to the polymer chains through hydrogen bonding, leading to their steady release for 168 h. An in vitro drug release study showed a burst effect followed by sustained release of LEV and QS from the nanofibers due to the Fickian diffusion. The NIH 3T3 fibroblast cell viability of the drug loaded core-shell nanofibers was comparable to that in the control (tissue culture polystyrene) implying biocompatibility of the nanofibers and their cell supportive role. However, there was no significant difference in cell viability between the drug loaded and drug free core-shell nanofibers. According to in vivo experiments, PEO-CS-LEV/PLGA-QS core-shell nanofibers could accelerate the healing process of a burn wound compared to a sterile gauze. Thanks to the synergistic therapeutic effect of LEV and QS, a significantly higher wound closure rate was recorded for the drug loaded core-shell nanofibrous dressing than the drug free nanofibers and control. Conclusively, PEO-CS-LEV/PLGA-QS core-shell nanofibers were shown to be a promising wound healing material that could drive the healing cascade through local co-delivery of LEV and QS to burn wounds.

Second Skin as Self-Protection Against γ-Hydroxybutyrate

γ-Hydroxybutyrate (GHB), a date-rape drug, causes certain symptoms, such as amnesia, confusion, ataxia, and unconsciousness, when dissolved in beverages and consumed by a victim. Commonly, assailants use GHB in secret for the crime of drug-facilitated sexual assault because it is tasteless, odorless, and colorless when dissolved in beverages. Generally, GHB detection methods are difficult to use promptly and secretly in situ and in real life because of the necessary detection equipment and low selectivity. To overcome this problem, we have developed a fast, simple, and easy-to-use second skin platform as a confidential self-protection platform that can detect GHB in situ or in real life without equipment. The second skin platform for naked-eye detection of GHB is fabricated with poly(vinyl alcohol) (PVA), polyurethane (PU), and polyacrylonitrile (PAN) included in the chemical receptor 2-(3-bromo-4-hydroxystyryl)-3-ethylbenzothiazol-3-ium iodide (BHEI). PAN conjugated with BHEI nanofibers (PB NFs) has various characteristics, such as ease of use, high sensitivity, and fast color change. PB NFs rapidly detected GHB at 0.01 mg/mL. Furthermore, the second-skin platform attached to the fingertip and wrist detected both 1 and 0.1 mg/mL GHB in solution within 50 s. The color changes caused by the interaction of GHB and the second skin platform cannot be stopped due to strong chemical reactions. In addition, a second skin platform can be secretly utilized in real life because it can recognize fingerprints and object temperatures. Therefore, the second skin platform can be used to aid daily life and prevent drug-facilitated sexual assault crime when attached to the skin because it can be exposed anytime and anywhere.

Electrospinning of bovine serum albumin-based nano-fibers: From synthesis to medical prospects; Challenges and future directions

Bovine serum albumin (BSA) is a globular non-glycoprotein that has gotten a lot of attention because of its unique properties like biocompatibility, biodegradability, non-immunogenicity, non-toxicity, and strong resemblance to the natural extracellular matrix (ECM). Given its robust mechanical properties, such as interfacial tension, conductivity, swelling resistance, and viscoelasticity, it can be concluded that it is an appropriate matrix for producing novel BSA-based nanoconstructs. Thus, simple analytic methods are required for accurately detecting BSA as a model protein in medical sciences and healthcare. Furthermore, the characteristics mentioned above aid BSA in the electrospinning process, which results in fibers conjugated with other polymers. Electrospun synthesis has recently received much attention for its ability to produce stable, biomimicking, highly porous, 3D BSA-derived nano-fibers. As a result, BSA-based nano-fibers have achieved exclusive developments in the medical sector, such as tissue engineering for the remodeling of damaged tissue or organ repair by creating artificial ones. Meanwhile, they could be used as drug delivery systems (DDS) for target-specific drug delivery, wound dressings, and so on. This study illustrates the structural and physicochemical properties of BSA and the determination of BSA using various methods, by citing recent reports and current developments in the medical field. Furthermore, current challenges and future directions are also highlighted.

State-of-the-Art Review of Advanced Electrospun Nanofiber Composites for Enhanced Wound Healing

Wound healing is a complex biological process with four main phases: hemostasis, inflammation, proliferation, and remodeling. Current treatments such as cotton and gauze may delay the wound healing process which gives a demand for more innovative treatments. Nanofibers are nanoparticles that resemble the extracellular matrix of the skin and have a large specific surface area, high porosity, good mechanical properties, controllable morphology, and size. Nanofibers are generated by electrospinning method that utilizes high electric force. Electrospinning device composed of high voltage power source, syringe that contains polymer solution, needle, and collector to collect nanofibers. Many polymers can be used in nanofiber that can be from natural or from synthetic origin. As such, electrospun nanofibers are potential scaffolds for wound healing applications. This review discusses the advanced electrospun nanofiber morphologies used in wound healing that is prepared by modified electrospinning techniques.

Biosynthesis of Zinc Oxide Nanoparticles on l-Carnosine Biofunctionalized Polyacrylonitrile Nanofibers; a Biomimetic Wound Healing Material

Multifunctional biohybrid nanofibers (NFs) that can simultaneously drive various cellular activities and confer antibacterial properties are considered desirable in producing advanced wound healing materials. In this study, a bionanohybrid formulation was processed as a NF wound dressing to stimulate the adhesion and proliferation of fibroblast and endothelial cells that play a major role in wound healing. Polyacrylonitrile (PAN) electrospun NFs were hydrolyzed using NaOH and biofunctionalized with l-carnosine (CAR), a dipeptide which could later biosynthesize zinc oxide (ZnO) nanoparticles (NPs) on the NFs surface. The morphological study verified that ZnO NPs are uniformly distributed on the surface of CAR/PAN NFs. Through EDX and XRD analysis, it was validated that the NPs are composed of ZnO and/or ZnO/Zn(OH)2. The presence of CAR and ZnO NPs brought about a superhydrophilicity effect and notably raised the elastic modulus and tensile strength of Zn-CAR/PAN NFs. While CAR ligands were shown to improve the viability of fibroblast (L929) and endothelial (HUVEC) cells, ZnO NPs lowered the positive impact of CAR, most likely due to their repulsive negative surface charge. A scratch assay verified that CAR/PAN NFs and Zn-CAR/PAN NFs aided HUVEC migration more than PAN NFs. Also, an antibacterial assay implied that CAR/PAN NFs and Zn-CAR/PAN NFs are significantly more effective in inhibiting Staphylococcus aureus (S. aureus) than neat PAN NFs are (1000 and 500%, respectively). Taken together, compared to the neat PAN NFs, CAR/PAN NFs with and without the biosynthesized ZnO NPs can support the cellular activities of relevance for wound healing and inactivate bacteria.

Wettability of Amino Acid-Functionalized PSMA Electrospun Fibers for the Modulated Release of Active Agents and Its Effect on Their Bioactivity

The ideal treatment for chronic wounds is based on the use of bioactive dressings capable of releasing active agents. However, the control of the rate at which these active agents are released is still a challenge. Bioactive polymeric fiber mats of poly(styrene-co-maleic anhydride) [PSMA] functionalized with amino acids of different hydropathic indices and L-glutamine, L-phenylalanine and L-tyrosine levels allowed obtaining derivatives of the copolymers named PSMA@Gln, PSMA@Phe and PSMA@Tyr, respectively, with the aim of modulating the wettability of the mats. The bioactive characteristics of mats were obtained by the incorporation of the active agents Calendula officinalis (Cal) and silver nanoparticles (AgNPs). A higher wettability for PSMA@Gln was observed, which is in accordance with the hydropathic index value of the amino acid. However, the release of AgNPs was higher for PSMA and more controlled for functionalized PSMA (PSMAf), while the release curves of Cal did not show behavior related to the wettability of the mats due to the apolar character of the active agent. Finally, the differences in the wettability of the mats also affected their bioactivity, which was evaluated in bacterial cultures of Staphylococcus aureus ATCC 25923 and methicillin-resistant Staphylococcus aureus ATCC 33592, an NIH/3T3 fibroblast cell line and red blood cells.

Cerium Oxide Nanoparticles/Polyacrylonitrile Nanofibers as Impervious Barrier against Viral Infections

BACKGROUND

Using face masks is one of the protective measures to reduce the transmission rate of coronavirus. Its massive spread necessitates developing safe and effective antiviral masks (filters) applying nanotechnology.

METHODS

Novel electrospun composites were fabricated by incorporating cerium oxide nanoparticles (CeO2 NPs) into polyacrylonitrile (PAN) electrospun nanofibers that can be used in the future in face masks. The effects of the polymer concentration, applied voltage, and feeding rate during the electrospinning were studied. The electrospun nanofibers were characterized using SEM, XRD, FTIR, and tensile strength testing. The cytotoxic effect of the nanofibers was evaluated in the Vero cell line using the MTT colorimetric assay, and the antiviral activity of the proposed nanofibers was evaluated against the human adenovirus type 5 (ADV-5) respiratory virus.

RESULTS

The optimum formulation was fabricated with a PAN concentration of 8%, w/v loaded with 0.25%, w/v CeO2 NPs with a feeding rate of 26 KV and an applied voltage of 0.5 mL/h. They showed a particle size of 15.8 ± 1.91 nm and a zeta potential of -14 ± 0.141 mV. SEM imaging demonstrated the nanoscale features of the nanofibers even after incorporating CeO2 NPs. The cellular viability study showed the safety of the PAN nanofibers. Incorporating CeO2 NPs into these fibers further increased their cellular viability. Moreover, the assembled filter could prevent viral entry into the host cells as well as prevent their replication inside the cells via adsorption and virucidal antiviral mechanisms.

CONCLUSIONS

The developed cerium oxide nanoparticles/polyacrylonitrile nanofibers can be considered a promising antiviral filter that can be used to halt virus spread.

Enhanced osteogenesis on proantocyanidin-loaded date palm endocarp cellulosic matrices: A novel sustainable approach for guided bone regeneration

Developing inexpensive, biocompatible natural scaffolds that can support the differentiation and proliferation of stem cells has been recently emphasized by the research community to faster obtain the FDA approvals for regenerative medicine. In this regard, plant-derived cellulose materials are a novel class of sustainable scaffolding materials with high potentials for bone tissue engineering (BTE). However, low bioactivity of the plant-derived cellulose scaffolds restricts cell proliferation and cell differentiation. This limitation can be addressed though surface-functionalization of cellulose scaffolds with natural antioxidant polyphenols, e.g., grape seed proanthocyanidin (PCA)-rich extract (GSPE). Despite the various merits of GSPE as a natural antioxidant, its impact on the proliferation and adhesion of osteoblast precursor cells, and on their osteogenic differentiation is an as-yet unknown issue. Here, we investigated the effects of GSPE surface functionalization on the physicochemical properties of decellularized date (Phoenix dactyliferous) fruit inner layer (endocarp) (DE) scaffold. In this regard, various physiochemical characteristics of the DE-GSPE scaffold such as hydrophilicity, surface roughness, mechanical stiffness, porosity, and swelling, and biodegradation behavior were compared with those of the DE scaffold. Additionally, the impact of the GSPE treatment of the DE scaffold on the osteogenic response of human mesenchymal stem cells (hMSCs) was thoroughly studied. For this purpose, cellular activities including cell adhesion, calcium deposition and mineralization, alkaline phosphatase (ALP) activity, and expression levels of bone-related genes were monitored. Taken together, the GSPE treatment enhanced the physicochemical and biological properties of the DE-GSPE scaffold, thereby raising its potentials as a promising candidate for guided bone regeneration.

A 3D-Printed Wound-Healing Material Composed of Alginate Dialdehyde-Gelatin Incorporating Astaxanthin and Borate Bioactive Glass Microparticles

In this study, a wound dressing composed of an alginate dialdehyde-gelatin (ADA-GEL) hydrogel incorporated by astaxanthin (ASX) and 70B (70:30 B₂O₃/CaO in mol %) borate bioactive glass (BBG) microparticles was developed through 3D printing. ASX and BBG particles stiffened the composite hydrogel construct and delayed its in vitro degradation compared to the pristine hydrogel construct, mainly due to their cross-linking role, likely arising from hydrogen bonding between the ASX/BBG particles and ADA-GEL chains. Additionally, the composite hydrogel construct could hold and deliver ASX steadily. The composite hydrogel constructs codelivered biologically active ions (Ca and B) and ASX, which should lead to a faster, more effective wound-healing process. As shown through in vitro tests, the ASX-containing composite hydrogel promoted fibroblast (NIH 3T3) cell adhesion, proliferation, and vascular endothelial growth factor expression, as well as keratinocyte (HaCaT) migration, thanks to the antioxidant activity of ASX, the release of cell-supportive Ca²⁺ and B³⁺ ions, and the biocompatibility of ADA-GEL. Taken together, the results show that the ADA-GEL/BBG/ASX composite is an attractive biomaterial to develop multipurposed wound-healing constructs through 3D printing.

Bioactive glass-based fibrous wound dressings

Since the discovery of silicate bioactive glass (BG) by Larry Hench in 1969, different classes of BGs have been researched over decades mainly for bone regeneration. More recently, validating the beneficial influence of BGs with tailored compositions on angiogenesis, immunogenicity and bacterial infection, the applicability of BGs has been extended to soft tissue repair and wound healing. Particularly, fibrous wound dressings comprising BG particle reinforced polymer nanofibers and cotton-candy-like BG fibers have been proven to be successful for wound healing applications. Such fibrous dressing materials imitate the physical structure of skin's extracellular matrix and release biologically active ions e.g. regenerative, pro-angiogenic and antibacterial ions, e.g. borate, copper, zinc, etc., that can provoke cellular activities to regenerate the lost skin tissue and to induce new vessels formation, while keeping an anti-infection environment. In the current review, we discuss different BG fibrous materials meant for wound healing applications and cover the relevant literature in the past decade. The production methods for BG-containing fibers are explained and as fibrous wound dressing materials, their wound healing and bactericidal mechanisms, depending on the ions they release, are discussed. The present gaps in this research area are highlighted and new strategies to address them are suggested.

Recent Progress in Electrospun Polyacrylonitrile Nanofiber-Based Wound Dressing

Bleeding control plays a very important role in worldwide healthcare, which also promotes research and development of wound dressings. The wound healing process involves four stages of hemostasis, inflammation, proliferation and remodeling, which is a complex process, and wound dressings play a huge role in it. Electrospinning technology is simple to operate. Electrospun nanofibers have a high specific surface area, high porosity, high oxygen permeability, and excellent mechanical properties, which show great utilization value in the manufacture of wound dressings. As one of the most popular reactive and functional synthetic polymers, polyacrylonitrile (PAN) is frequently explored to create nanofibers for a wide variety of applications. In recent years, researchers have invested in the application of PAN nanofibers in wound dressings. Research on spun nanofibers is reviewed, and future development directions and prospects of electrospun PAN nanofibers for wound dressings are proposed.

Preparation of CO2 -based Cationic Polycarbonate/Polyacrylonitrile Nanofibers with an Optimal Fibrous Microstructure for Antibacterial Applications

Utilizing CO₂ as one of the monomer resource, poly(vinylcyclohexene carbonates) (PVCHCs) are used as the precursor for preparing cationic PVCHCs (CPVCHCs) via thiol-ene click functionalization. Through the functionalization, CPVCHC-43 with a tertiary amine density of 43% relative to the backbone is able to display a significantly antibacterial ability against Staphylococcus aureus (S. aureus). Blending CPVCHC-43 with polyacrylonitrile (PAN), CPVCHC/PAN nanofiber meshes (NFMs) have been successfully prepared by electrospinning. More importantly, two crucial fibrous structural factors including CPVCHC/PAN weight ratio and fiber diameter have been systematically investigated for the effects on the antibacterial performance of the NFMs. Sequentially, a quaternization treatment has been employed on the NFMs with an optimal fibrous structure to enhance the antibacterial ability. The resulting quaternized NFMs have demonstrated the great biocidal effects against Gram-positive and Gram-negative bacteria. Moreover, the excellent biocompatibility of the quaternized NFMs have also been thoroughly evaluated and verified. This article is protected by copyright. All rights reserved.

A 3D Printed Bone Tissue Engineering Scaffold Composed of Alginate Dialdehyde-Gelatine Reinforced by Lysozyme Loaded Cerium Doped Mesoporous Silica-Calcia Nanoparticles

A novel biomaterial comprising alginate dialdehyde-gelatine (ADA-GEL) hydrogel augmented by lysozyme loaded mesoporous cerium doped silica-calcia nanoparticles (Lys-Ce-MSNs) was 3D printed to create bioactive scaffolds. Lys-Ce-MSNs raised the mechanical stiffness of the hydrogel composite scaffold and induced surface apatite mineralization, when the scaffold was immersed in simulated body fluid (SBF). Moreover, the scaffolds could co-deliver bone healing (Ca and Si) and antioxidant ions (Ce), and Lys to achieve antibacterial (and potentially anticancer) properties. The nanocomposite hydrogel scaffolds could hold and deliver Lys steadily. Based on the in vitro results, the hydrogel nanocomposite containing Lys assured improved pre-osteoblast cell (MC3T3-E1) proliferation, adhesion, and differentiation, thanks to the biocompatibility of ADA-GEL, bioactivity of Ce-MSNs, and the stabilizing effect of Lys on the scaffold structure. On the other hand, the proliferation level of MG63 osteosarcoma cells decreased, likely due to the anticancer effect of Lys. Last but not least, cooperatively, alongside gentamicin (GEN), Lys brought about a proper antibacterial efficiency to the hydrogel nanocomposite scaffold against gram-positive and gram-negative bacteria. Taken together, ADA-GEL/Lys-Ce-MSN nanocomposite holds great promise for 3D printing of multifunctional hydrogel BTE scaffolds, able to induce bone regeneration, address infection, and potentially inhibit tumor formation and growth. This article is protected by copyright. All rights reserved.

Inhibition of SARS-CoV-2 spike protein entry using biologically modified polyacrylonitrile nanofibers: in vitro study towards specific antiviral masks

With the increase of the contagiousness rates of Coronavirus disease (COVID-19), new strategies are needed to halt virus spread. Blocking virus entry by capturing its spike (S) protein is one of the effective approaches that could help in eliminating or reducing transmission rate of viruses. Herein, we aim to develop a nanofiber-based filter for protective face masks, composed of polyacrylonitrile (PAN) nanofibers (NFs)-loaded with Angiotensin Converting Enzyme-2 (ACE-2) for capturing the spike protein of severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2) and blocking its entry. Docking simulations were performed to evaluate interactions of PAN with target proteins of both SARS-CoV-2 and Human Adenovirus type 5 (ADV-5) which was used as an in vitro model of human respiratory viruses. Scanning electron microscopy (SEM) and Fourier transformed infrared (FT-IR) spectroscopy was employed to investigate the surface morphology and to analyze the functional groups of the NFs, respectively. The mechanical properties of the electrospun NFs were investigated, according to which the tensile strengths of PAN and modified PAN NFs were 4.9 ± 1.2 GPa and 4.5 GPa. Additionally, elongations at break were 25 ± 2.5% to 24 ± 1.48% for PAN and modified PAN NFs. The tensile strength test showed good mechanical characteristics of the NFs. The ACE-2-loaded NFs were shown to be safe, with promising antiviral activity towards ADV-5. Meanwhile, a binding affinity study between the spike protein and ACE-2 was performed and the dissociation constant (K D) was found to be 1.1 nM. Accordingly, the developed antiviral filters have a potential role to stand as a base for combating various human respiratory viruses.

Nature-Derived and Synthetic Additives to poly(ɛ-Caprolactone) Nanofibrous Systems for Biomedicine; an Updated Overview

As a low cost, biocompatible, and bioresorbable synthetic polymer, poly (ɛ-caprolactone) (PCL) is widely used for different biomedical applications including drug delivery, wound dressing, and tissue engineering. An extensive range of in vitro and in vivo tests has proven the favourable applicability of PCL in biomedicine, bringing about the FDA approval for a plethora of PCL made medical or drug delivery systems. This popular polymer, widely researched since the 1970s, can be readily processed through various techniques such as 3D printing and electrospinning to create biomimetic and customized medical products. However, low mechanical strength, insufficient number of cellular recognition sites, poor bioactivity, and hydrophobicity are main shortcomings of PCL limiting its broader use for biomedical applications. To maintain and benefit from the high potential of PCL, yet addressing its physicochemical and biological challenges, blending with nature-derived (bio)polymers and incorporation of nanofillers have been extensively investigated. Here, we discuss novel additives that have been meant for enhancement of PCL nanofiber properties and thus for further extension of the PCL nanofiber application domain. The most recent researches (since 2017) have been covered and an updated overview about hybrid PCL nanofibers is presented with focus on those including nature-derived additives, e.g., polysaccharides and proteins, and synthetic additives, e.g., inorganic and carbon nanomaterials.

Electrospun Fibers Derived from Peptide Coupled Amphiphilic Copolymers for Dorsal Root Ganglion (DRG) Outgrowth

Developing scaffolds with appropriate mechanical/structural features as well as tunable bioactivities are indispensable in the field of tissue engineering. This study focused on one such attempt to electrospin the copolymer of L-lactic acid (L-LA) and functional monomer (3(S)- [(benzyloxycarbony)methyl]-1,4-dioxane-2,5-dione, BMD) with small peptide modifications for the purpose of neural tissue engineering. Scanning Electron Microscopy (SEM) micrographs showed fabricated electrospun copolymer as porous and uniform nanofibrous materials with diameter in the range of 800-1000 nm. In addition, the modified scaffolds displayed a lower contact angle than poly(L-lactide) (PLLA) indicating higher hydrophilicity. To further incorporate the bioactive functions, the nanofibers were chemically coupled with small peptide (isoleucine-lysine-valine-alanine-valine, IKVAV). The incorporation of IKVAV onto the electrospun fiber was confirmed by X-ray photoelectron spectroscopy (XPS) and such incorporation did not affect the surface morphology or fiber diameters. To demonstrate the potential of applying the designed scaffolds for nerve regeneration, dorsal root ganglion (DRG) neurons were cultured on the nanofibers to examine the impact on neurite outgrowth of DRGs. The results indicated that the fabricated nanofibrous matrix with small peptide might be a potential candidate for neural tissue engineering.

Functionalized Porous Hydroxyapatite Scaffolds for Tissue Engineering Applications: A Focused Review

Biomaterials have been widely used in tissue engineering applications at an increasing rate in recent years. The increased clinical demand for safe scaffolds, as well as the diversity and availability of biomaterials, has sparked rapid interest in fabricating diverse scaffolds to make significant progress in tissue engineering. Hydroxyapatite (HAP) has drawn substantial attention in recent years owing to its excellent physical, chemical, and biological properties and facile adaptable surface functionalization with other innumerable essential materials. This focused review spotlights a brief introduction on HAP, scope, a historical outline, basic structural features/properties, various synthetic strategies, and their scientific applications concentrating on functionalized HAP in the diverse area of tissue engineering fields such as bone, skin, periodontal, bone tissue fixation, cartilage, blood vessel, liver, tendon/ligament, and corneal are emphasized. Besides clinical translation aspects, the future challenges and prospects of HAP based biomaterials involved in tissue engineering are also discussed. Furthermore, it is expected that researchers may find this review expedient in gaining an overall understanding of the latest advancement of HAP based biomaterials.

The effect of chemical structure of carboxylate molecules on hydroxyapatite nanoparticles. A structural and morphological study

Being the most abundant non-macromolecular organic component of bone, the role of citrate (Cit) in hydroxyapatite (HA) crystallization is of high relevance. In this work we have investigated the influence of hydroxycitrate (CitOH) and glutarate (Glr) on HA crystallization in terms of particle growth, composition, and morphology in comparison to Cit. CitOH and Glr have been selected for this work because they share the same backbone structure of Cit but bear different functional groups in the central region. Our data has revealed that CitOH strongly inhibits HA crystallization more efficiently than Cit. CitOH-HA nanoparticles are composed of platy, elongated particles similar to those of Cit-HA but they are ca. twice smaller and have a lower crystal order. On the other hand, Glr does not inhibit HA crystallization as Cit, but leads to the formation of OCP platelets that convert with maturation time to HA nanorods with larger aspect ratio than Cit-HA. In comparison to Cit-HA samples, Glr-HA nanoparticles have bigger dimensions, and higher structural order. Overall, our data reveal that the central carboxyl group of Cit is involved in the selective binding with HA crystal surface and in regulating HA crystal growth. The results of this work highlight new possibilities to control the formation of HA for designing advanced bioactive materials and give new insights on the role of the structure of Cit in regulating the HA morphology.

Experimental Dental Composites Containing a Novel Methacrylate-Functionalized Calcium Phosphate Component: Evaluation of Bioactivity and Physical Properties

The aim of this study was to synthesize and characterize a novel methacrylate-functionalized calcium phosphate (MCP) to be used as a bioactive compound for innovative dental composites. The characterization was accomplished by attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The incorporation of MCP as a bioactive filler in esthetic dental composite formulations and the ability of MCP containing dental composites to promote the precipitation of hydroxyapatite (HAp) on the surfaces of those dental composites was explored. The translucency parameter, depth of cure, degree of conversion, ion release profile, and other physical properties of the composites were studied with respect to the amount of MCP added to the composites. Composite with 3 wt.% MCP showed the highest flexural strength and translucency compared to the control composite and composites with 6 wt.% and 20 wt.% MCP. The progress of the surface precipitation of hydroxyapatite on the MCP containing dental composites was studied by systematically increasing the MCP content in the composite and the time of specimen storage in Dulbecco's phosphate-buffered solution with calcium and magnesium. The results suggested that good bioactivity properties are exhibited by MCP containing composites. A direct correlation between the percentage of MCP in a composite formulation, the amount of time the specimen was stored in PBS, and the deposition of hydroxyapatite on the composite's surface was observed.

Artificial Bioaugmentation of Biomacromolecules and Living Organisms for Biomedical Applications

The synergistic union of nanomaterials with biomaterials has revolutionized synthetic chemistry, enabling the creation of nanomaterial-based biohybrids with distinct properties for biomedical applications. This class of materials has drawn significant scientific interest from the perspective of functional extension via controllable coupling of synthetic and biomaterial components, resulting in enhancement of the chemical, physical, and biological properties of the obtained biohybrids. In this review, we highlight the forefront materials for the combination with biomacromolecules and living organisms and their advantageous properties as well as recent advances in the rational design and synthesis of artificial biohybrids. We further illustrate the incredible diversity of biomedical applications stemming from artificially bioaugmented characteristics of the nanomaterial-based biohybrids. Eventually, we aim to inspire scientists with the application horizons of the exciting field of synthetic augmented biohybrids.

Colorimetric glucose sensing with multiple-color changes by using a MnO2 NSs-TMB nanosystem

Glucose performs many essential functions associated with metabolic processes in the living system, and is closely related to many diseases such as diabetes and hypoglycemia. Most of the existing glucose concentration detection methods require complex instruments, which undoubtedly limit its widespread use. Here, we have designed a glucose colorimetric detection system composed of glucose, glucose oxidase (GOD), manganese dioxide nanosheets (MnO₂ NSs) and 3,3',5,5'-tetramethylbenzidine (TMB) to achieve colorimetric detection with the naked eye. Compared with the single-color change of the colorimetric method in previous studies, multiple-color changes have been realized. MnO₂ NSs, as a kind of nanomaterial imitating oxidase, can directly oxidize TMB to oxTMB. Because oxTMB showed a dark yellow color when strongly oxidized and light blue when weakly oxidized, this feature can achieve multiple-color changes rather than a single-color change, which is helpful for colorimetric observation with the naked eye. Finally, we successfully used MnO₂ NSs for colorimetric detection of glucose and realized multiple-color changes, making it easier to achieve colorimetric observation with the naked eye. The linear detection range is 0-4000 μM and limit of detection is 5.0 μM. This is not only useful for glucose, but also has an important significance for other experiments considering colorimetric experiments with the naked eye.

Biomimetic biohybrid nanofibers containing bovine serum albumin as a bioactive moiety for wound dressing

For the first time, a biohybrid nanofibrous wound dressing is developed via green electrospinning of a blend solution of bovine serum albumin (BSA) (1 and 3 wt%) and polycaprolactone (PCL). In such a system, the components are miscible and interact through hydrogen bonding between the carbonyl group of PCL and the amine group of BSA, as verified by ATR-FTIR. As a result, the biohybrid nanofibers show a superior elastic modulus and elongation (300% and 58%, respectively) compared with the neat PCL nanofibers. The included protein induces a hydrophilicity effect to the PCL nanofibers, notably at the higher BSA content (3 wt%). In contrast to the neat nanofibers, the biohybrid ones are bioactive and encourage formation of biominerals (made of amorphous calcium carbonate) on the surface, after immersion in simulated body fluid (SBF). Based on the WST-8 cell viability tests, NIH3T3 fibroblast cells were seen to properly interact with the biohybrid mats and to proliferate in their proximity. SEM images show that the cells largely adhere onto such nanofibers even more than they do on the neat ones and adopt a flattened and stretched shape. In addition, the live/dead assay and phalloidin/DAPI staining assay confirm large cell viability and normal cell morphology on the biohybrid nanofiber mats after 4 days incubation. Taken together, BSA/PCL nanofibers are able to offer optimum mechanical properties (elasticity) as well as mineralization which can potentially stimulate the wound healing process, and can be considered a suitable candidate for wound dressing applications.

Recent Advances in Biopolymeric Composite Materials for Tissue Engineering and Regenerative Medicines: A Review

The polymeric composite material with desirable features can be gained by selecting suitable biopolymers with selected additives to get polymer-filler interaction. Several parameters can be modified according to the design requirements, such as chemical structure, degradation kinetics, and biopolymer composites' mechanical properties. The interfacial interactions between the biopolymer and the nanofiller have substantial control over biopolymer composites' mechanical characteristics. This review focuses on different applications of biopolymeric composites in controlled drug release, tissue engineering, and wound healing with considerable properties. The biopolymeric composite materials are required with advanced and multifunctional properties in the biomedical field and regenerative medicines with a complete analysis of routine biomaterials with enhanced biomedical engineering characteristics. Several studies in the literature on tissue engineering, drug delivery, and wound dressing have been mentioned. These results need to be reviewed for possible development and analysis, which makes an essential study.

Formation and Photoluminescence Properties of ZnO Nanoparticles on Electrospun Nanofibers Produced by Atomic Layer Deposition

The unique combination of optical, chemical, and structural properties of one-dimensional zinc oxide (1D ZnO) makes it one of the most attractive materials in a wide range of research and applications. In the present study, 1D ZnO nanomaterials were fabricated using a combination of two independent methods: electrospinning and atomic layer deposition (ALD). The electrospinning technique was used to produce 1D electrospun fibers consisting of four types of polymers: polylactic acid (PLLA), polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), and polyamide 6 (PA6). The ALD technology, in turn, was selected as an excellent candidate for the synthesis of a ZnO thin layer over polymer fibers for the production of 1D ZnO/polymer nanofiber composites (PLLA/ZnO, PVDF/ZnO, PVA/ZnO, PA6/ZnO). Structural and optical properties of the produced nanofibers were studied by means of scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), diffuse reflectance, and photoluminescence (PL) spectroscopy. It was found that only PVDF/ZnO nanofibers exhibit stable room temperature PL that may be the result of a higher ZnO content in the sample. In addition, PL measurements were conducted as a function of excitation power and temperature in order to establish the main PL mechanisms and parameters for the PVDF/ZnO sample, as a most promising candidate for the biophotonic application.

Bioactive Glasses: A Promising Therapeutic Ion Release Strategy for Enhancing Wound Healing

The morbidity, mortality, and burden of burn victims and patients with severe diabetic wounds are still high, which leads to an extensively growing demand for novel treatments with high clinical efficacy. Biomaterial-based wound treatment approaches have progressed over time from simple cotton wool dressings to advanced skin substitutes containing cells and growth factors; however, no wound care approach is yet completely satisfying. Bioactive glasses are materials with potential in many areas that exhibit unique features in biomedical applications. Today, bioactive glasses are not only amorphous solid structures that can be used as a substitute in hard tissue but also are promising materials for soft tissue regeneration and wound healing applications. Biologically active elements such as Ag, B, Ca, Ce, Co, Cu, Ga, Mg, Se, Sr, and Zn can be incorporated in glass networks; hence, the superiority of these multifunctional materials over current materials results from their ability to release multiple therapeutic ions in the wound environment, which target different stages of the wound healing process. Bioactive glasses and their dissolution products have high potency for inducing angiogenesis and exerting several biological impacts on cell functions, which are involved in wound healing and some other features that are valuable in wound healing applications, namely hemostatic and antibacterial properties. In this review, we focus on skin structure, the dynamic process of wound healing in injured skin, and existing wound care approaches. The basic concepts of bioactive glasses are reviewed to better understand the relationship between glass structure and its properties. We illustrate the active role of bioactive glasses in wound repair and regeneration. Finally, research studies that have used bioactive glasses in wound healing applications are summarized and the future trends in this field are elaborated.