Injectable, Antioxidative, and Tissue-Adhesive Nanocomposite Hydrogel as a Potential Treatment for Inner Retina Injuries.

Reactive oxygen species (ROS) have been recognized as prevalent contributors to the development of inner retinal injuries including optic neuropathies such as glaucoma, non-arteritic anterior ischemic optic neuropathy, traumatic optic neuropathy, and Leber hereditary optic neuropathy, among others. This underscores the pivotal significance of oxidative stress in the damage inflicted upon retinal tissue. To combat ROS-related challenges, this study focuses on creating an injectable and tissue-adhesive hydrogel with tailored antioxidant properties for retinal applications. GelCA, a gelatin-modified hydrogel with photo-crosslinkable and injectable properties, is developed. To enhance its antioxidant capabilities, curcumin-loaded polydopamine nanoparticles (Cur@PDA NPs) are incorporated into the GelCA matrix, resulting in a multifunctional nanocomposite hydrogel referred to as Cur@PDA@GelCA. This hydrogel exhibits excellent biocompatibility in both in vitro and in vivo assessments, along with enhanced tissue adhesion facilitated by NPs in an in vivo model. Importantly, Cur@PDA@GelCA demonstrates the potential to mitigate oxidative stress when administered via intravitreal injection in retinal injury models such as the optic nerve crush model. These findings underscore its promise in advancing retinal tissue engineering and providing an innovative strategy for acute neuroprotection in the context of inner retinal injuries.

Antioxidant Nanoparticles Restore Cisplatin-Induced Male Fertility Defects by Promoting MDC1-53bp1-Associated Non-Homologous DNA Repair Mechanism and Sperm Intracellular Calcium Influx.

Introduction: Cisplatin, a commonly used anticancer compound, exhibits severe off-target organ toxicity. Due to its wide application in cancer treatment, the reduction of its damage to normal tissue is an imminent clinical need. Cisplatin-induced testicular oxidative stress and damage lead to male sub- or infertility. Despite earlier studies showing that the natural polyphenol extracts honokiol serve as the free radical scavenger that reduces the accumulation of intracellular free radicals, whether honokiol exhibits direct effects on the testis and sperm is unclear. Thus, the aim of the current study is to investigate the direct effects of honokiol on testicular recovery and sperm physiology. Methods: We encapsulated this polyphenol antioxidation compound into liposome-based nanoparticles (nHNK) and gave intraperitoneally to mice at a dosage of 5 mg/kg body mass every other day for consecutive 6 weeks. Results: We showed that nHNK promotes MDC1-53bp1-associated non-homologous DNA double-strand break repair signaling pathway that minimizes cisplatin-induced DNA damage. This positive effect restores spermatogenesis and allows the restructuring of the multi-spermatogenic layers in the testis. By reducing mitochondrial oxidative damage, nHNK also protects sperm mitochondrial structure and maintains both testicular and sperm ATP production. By a yet-to-identify mechanism, nHNK restores sperm calcium influx at the sperm midpiece and tail, which is essential for sperm hypermotility and their interaction with the oocyte. Discussion: Taken together, the nanoparticulated antioxidant counteracts cisplatin-induced male fertility defects and benefits patients undertaking cisplatin-based chemotherapy. These data may allow the reintroduction of cisplatin for systemic applications in patients at clinics with reduced testicular toxicity.

Alveolar mucosal cell spheroids promote extraction socket healing and osseous defect regeneration.

BACKGROUND: Alveolar mucosa could be a promising source of mesenchymal stem cells (MSCs) for regeneration therapeutics because it exhibits faster healing potential and can be easily collected with minimal periodontal disturbance. This study aimed to evaluate the potential of alveolar mucosal cell (AMC) spheroids for promoting extraction socket healing and calvarial osseous defect regeneration. METHODS: AMCs were isolated from Sprague-Dawley rats. Antigenic and MSC surface marker expressions and trilineage differentiation capability were assessed. AMCs were then osteogenically stimulated (OAs) or unstimulated (UAs), self-aggregated to form spheroids, and encapsulated in gelatin hydrogel to fill rat extraction sockets or combined with freeze-dried bone graft (FDBG) to fill rat calvarial osseous defects. The outcome was assessed by gross observation, micro-CT imaging, and immunohistochemistry. RESULTS: AMCs highly expressed MSC surface markers, showed weak antigenicity, and were capable of trilineage differentiation at Passage 3. In the extraction sockets, wound closure, socket fill, keratinization, and proliferative activities were accelerated in those with AMC spheroids treatment. Socket fill and maturation were further promoted by OA spheroids. In the calvarial osseous defects, the mineralized tissue ratio was promoted with AMC spheroids/FDBG treatment, and bone sialoprotein expression and cell proliferation were more evident with OA spheroids/FDBG treatment. CONCLUSION: AMCs exhibited MSC properties with weak antigenicity. AMC spheroids promoted extraction socket healing, AMC spheroids/FDBG promoted calvarial osseous defect regeneration, and the outcomes were further enhanced by osteogenically stimulation of AMCs.

Fabrication of triple-crosslinked gelatin/alginate hydrogels for controlled release applications.

Hydrogels have been demonstrated as smart drug carriers to recognize the tumor microenvironment for cancer treatment, where the dynamic crosslinks in the hydrogel network contribute to the stimuli-responsive features but also result in poor stability and weak mechanical property of the hydrogels. Here, phenylboronic acid-grafted polyethyleneimine (PBA-PEI)-modified gelatin (PPG) was synthesized to crosslink alginate dialdehyde (ADA) through imine bonds and boronate ester bonds, and then calcium ions (Ca2+) were added to introduce the third calcium-carboxylate crosslinking in the network to form the triple-crosslinked PPG/ADA-Ca2+ hydrogels. Given the three types of dynamic bonds in the network, PPG/ADA-Ca2+ hydrogels possessed a self-healing manner, stimuli-responsiveness, and better mechanical properties compared to single- or double-crosslinked hydrogels. The controlled release capability of PPG/ADA-Ca2+ hydrogels was also demonstrated, showing the encapsulated molecules can be rapidly released from the hydrogel network in the presence of hydrogen peroxide while the release rate can be slowed down at acidic pH. Furthermore, PPG/ADA-Ca2+ hydrogels presented selected cytotoxicity and drug delivery to cancer cells due to the regulated degradation by the cellular microenvironment. Taken together, PPG/ADA-Ca2+ hydrogels have been demonstrated as promising biomaterials with multiple desirable properties and dynamic features to perform controlled molecule release for biomedical applications.

Biophysical Electrical and Mechanical Stimulations for Promoting Chondrogenesis of Stem Cells on PEDOT:PSS Conductive Polymer Scaffolds.

The investigation of the effects of electrical and mechanical stimulations on chondrogenesis in tissue engineering scaffolds is essential for realizing successful cartilage repair and regeneration. The aim of articular cartilage tissue engineering is to enhance the function of damaged or diseased articular cartilage, which has limited regenerative capacity. Studies have shown that electrical stimulation (ES) promotes mesenchymal stem cell (MSC) chondrogenesis, while mechanical stimulation (MS) enhances the chondrogenic differentiation capacity of MSCs. Therefore, understanding the impact of these stimuli on chondrogenesis is crucial for researchers to develop more effective tissue engineering strategies for cartilage repair and regeneration. This study focuses on the preparation of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) conductive polymer (CP) scaffolds using the freeze-drying method. The scaffolds were fabricated with varying concentrations (0, 1, 3, and 10 wt %) of (3-glycidyloxypropyl) trimethoxysilane (GOPS) as a crosslinker and an additive to tailor the scaffold properties. To gain a comprehensive understanding of the material characteristics and the phase aggregation phenomenon of PEDOT:PSS scaffolds, the researchers performed theoretical calculations of solubility parameters and surface energies of PSS, PSS-GOPS, and PEDOT polymers, as well as conducted material analyses. Additionally, the study investigated the potential of promoting chondrogenic differentiation of human adipose stem cells by applying external ES or MS on a PEDOT:PSS CP scaffold. Compared to the group without stimulation, the group that underwent stimulation exhibited significantly up-regulated expression levels of chondrogenic characteristic genes, such as SOX9 and COL2A1. Moreover, the immunofluorescence staining images exhibited a more vigorous fluorescence intensity of SOX9 and COL II proteins that was consistent with the trend of the gene expression results. In the MS experiment, the strain excitation exerted on the scaffold was simulated and transformed into stress. The simulated stress response showed that the peak gradually decreased with time and approached a constant value, with the negative value of stress representing the generation of tensile stress. This stress response quantification could aid researchers in determining specific MS conditions for various materials in tissue engineering, and the applied stress conditions could be further optimized. Overall, these findings are significant contributions to future research on cartilage repair and biophysical ES/MS in tissue engineering.

Plasma-Derived Nanoclusters for Site-Specific Multimodality Photo/Magnetic Thrombus Theranostics.

Traditional thrombolytic therapeutics for vascular blockage are affected by their limited penetration into thrombi, associated off-target side effects, and low bioavailability, leading to insufficient thrombolytic efficacy. It is hypothesized that these limitations can be overcome by the precisely controlled and targeted delivery of thrombolytic therapeutics. A theranostic platform is developed that is biocompatible, fluorescent, magnetic, and well-characterized, with multiple targeting modes. This multimodal theranostic system can be remotely visualized and magnetically guided toward thrombi, noninvasively irradiated by near-infrared (NIR) phototherapies, and remotely activated by actuated magnets for additional mechanical therapy. Magnetic guidance can also improve the penetration of nanomedicines into thrombi. In a mouse model of thrombosis, the thrombosis residues are reduced by ≈80% and with no risk of side effects or of secondary embolization. This strategy not only enables the progression of thrombolysis but also accelerates the lysis rate, thereby facilitating its prospective use in time-critical thrombolytic treatment.

An in vitro analysis of the hemostatic efficacy of fibrinogen precipitation with varied keratin fraction compositions.

In preclinical studies, human hair has demonstrated effective hemostatic properties, potentially attributed to keratin proteins facilitating rapid conversion of fibrinogen to fibrin during coagulation. However, the rational use of human hair keratin for hemostasis remains unclear, given its complex mixture of proteins with diverse molecular weights and structures, leading to variable hemostatic capacity. To optimize the rational utilization of human hair keratin for hemostasis, we investigated the effects of different keratin fractions on keratin-mediated fibrinogen precipitation using a fibrin generation assay. Our study focused on high molecular weight keratin intermediate filaments (KIFs) and lower molecular weight keratin-associated proteins (KAPs) combined in various ratios during the fibrin generation. Scanning electron microscope analysis of the precipitates revealed a filamentous pattern with a broad distribution of fiber diameters, likely due to the diversity of keratin mixtures involved. An equal proportion of KIFs and KAPs in the mixture yielded the most extensive precipitation of soluble fibrinogen in an in vitro study, potentially due to structure-induced exposure of active sites. However, all hair protein samples exhibited diverse catalytic behaviors compared to thrombin, highlighting the potential of utilizing specific hair fractions to develop hair protein-based hemostatic materials with optimized capacity.

A Biomimicking and Multiarm Self-Indicating Nanoassembly for Site-Specific Photothermal-Potentiated Thrombolysis Assessed in Microfluidic and In Vivo Models.

Thrombolytic and antithrombotic therapies are limited by short circulation time and the risk of off-target hemorrhage. Integrating a thrombus-homing strategy with photothermal therapy are proposed to address these limitations. Using glycol chitosan, polypyrrole, iron oxide and heparin, biomimicking GCPIH nanoparticles are developed for targeted thrombus delivery and thrombolysis. The nanoassembly achieves precise delivery of polypyrrole, exhibiting biocompatibility, selective accumulation at multiple thrombus sites, and enhanced thrombolysis through photothermal activation. To simulate targeted thrombolysis, a microfluidic model predicting thrombolysis dynamics in realistic pathological scenarios is designed. Human blood assessments validate the precise homing of GCPIH nanoparticles to activated thrombus microenvironments. Efficient near-infrared phototherapeutic effects are demonstrated at thrombus lesions under physiological flow conditions ex vivo. The combined investigations provide compelling evidence supporting the potential of GCPIH nanoparticles for effective thrombus therapy. The microfluidic model also offers a platform for advanced thrombolytic nanomedicine development.

PEDOT:PSS-Based Bioelectrodes for Multifunctional Drug Release and Electric Cell-Substrate Impedance Sensing.

Electric cell-substrate impedance sensing (ECIS) is an innovative approach for the label-free and real-time detection of cell morphology, growth, and apoptosis, thereby playing an essential role as both a viable alternative and valuable complement to conventional biochemical/pharmaceutical analysis in the field of diagnostics. Constant improvements are naturally sought to further improve the effective range and reliability of this technology. In this study, we developed poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) conducting polymer (CP)-based bioelectrodes integrated into homemade ECIS cell-culture chamber slides for the simultaneous drug release and real-time biosensing of cancer cell viability under drug treatment. The CP comprised tailored PEDOT:PSS, poly(ethylene oxide) (PEO), and (3-glycidyloxypropyl)trimethoxysilane (GOPS) capable of encapsulating antitumor chemotherapeutic agents such as doxorubicin (DOX), docetaxel (DTX), and a DOX/DTX combination. This device can reliably monitor impedance signal changes correlated with cell viability on chips generated by cell adhesion onto a predetermined CP-based working electrode while simultaneously exhibiting excellent properties for both drug encapsulation and on-demand release from another CP-based counter electrode under electrical stimulation (ES) operation. Cyclic voltammetry curves and surface profile data of different CP-based coatings (without or with drugs) were used to analyze the changes in charge capacity and thickness, respectively, thereby further revealing the correlation between their drug-releasing performance under ES operation (determined using ultraviolet-visible (UV-vis) spectroscopy). Finally, antitumor drug screening tests (DOX, DTX, and DOX/DTX combination) were performed on MCF-7 and HeLa cells using our developed CP-based ECIS chip system to monitor the impedance signal changes and their related cell viability results.

Adipose-derived stem cell spheroid-laden microbial transglutaminase cross-linked gelatin hydrogel for treating diabetic periodontal wounds and craniofacial defects.

BACKGROUND: Diabetes mellitus deteriorates the destruction and impairs the healing of periodontal wounds and craniofacial defects. This study is to evaluate the potential of self-assembled adipose-derived stem cell spheroids (ADsp) in microbial transglutaminase cross-linked gelatin hydrogel (mTG) for treating diabetic periodontal wounds and craniofacial defects. METHODS: Human adipose-derived stem cells (ADSCs) were isolated by lipoaspiration, pluripotent genes and trilineage differentiation were examined, and the maintenance of ADsp properties in mTG was verified. Oral mucosal wounds and calvarial osseous defects were created in diabetic rats. Gross observation, histologic evaluation, and immunohistochemistry for proliferating cells and keratinization were conducted in the mucosal wounds within 4-28 days. Micro-CT imaging, histologic evaluation, and immunohistochemistry for proliferating cells and osteogenic differentiation were conducted in the osseous defects at 7 and 28 days. RESULTS: ADSCs expressed pluripotent genes and were capable of trilineage differentiation. ADsp retained morphology and stemness in mTG. In diabetic mucosal wounds, wound closure, epithelization, and keratinization were accelerated in those with ADsp and ADsp-mTG. In diabetic osseous defects, osteogenic differentiation markers were evidently expressed, cell proliferation was promoted from day 7, and bone formation was significantly promoted at day 28 in those with osteogenically pretreated ADsp-mTG. CONCLUSIONS: ADsp-mTG accelerated diabetic oral mucosal wound healing, and osteogenically pretreated ADsp-mTG promoted diabetic osseous defect regeneration, proving that ADsp-mTG facilitated diabetic periodontal wound healing and craniofacial osseous defect regeneration.

Fabrication of an Au-doped Cu/Fe oxide-polymer core-shell nanoreactor with chemodynamic and photodynamic dual effects as potential cancer therapeutic agents.

Nanoparticles are widely used in biomedical applications and cancer treatments due to their minute scale, multi-function, and long retention time. Among the various nanoparticles, the unique optical property derived from the localized surface plasmon resonance effect of metallic nanoparticles is a primary reason that metallic nanoparticles are researched and applied. Copper and Iron nanoparticles have the potential to generate hydroxyl radicals in excess H2O2 via Fenton or Fenton-like reactions. On the other hand, gold nanoparticles equipped with a photosensitizer can transfer the energy of photons to chemical energy and enhance the production of singlet oxygen, which is suitable for cancer treatment. With the actions of these two reactive oxygen species in the tumor microenvironment, cell apoptosis can further be induced. In this work, we first synthesized dual metal nanoparticles with poly[styrene-alt-(maleic acid, sodium salt)(Cu ferrite oxide-polymer) by a simple one-step hydrothermal reduction reaction. Then, gold(III) was reduced and doped into the structure, which formed a triple metal structure, Au-doped Cu ferrite nanoparticles (Au/Cu ferrite oxide-polymer NPs). The metal ratio of the product could be controlled by manipulating the Fe/Cu ratio of reactants and the sequence of addition of reactants. The core-shell structure was verified by transmission electron microscopy. Moreover, the hydroxyl radical and singlet oxygen generation ability of Au/Cu ferrite oxide-polymer was proved. The chemodynamic and photodynamic effect was measured, and the in vitro ROS generation was observed. Furthermore, the behavior of endocytosis by cancer cells could be controlled by the magnetic field. The result indicated that Au/Cu ferrite oxide-polymer core-shell nanoreactor is a potential agent for chemodynamic/photodynamic synergetic therapy.

Design and Investigation of an Eco-Friendly Wound Dressing Composed of Green Bioresources- Soy Protein, Tapioca Starch, and Gellan Gum.

In the fields of biomedicine and tissue engineering, natural polymer-based tissue-engineered scaffolds are used in multiple applications. As a plant-derived polymer, soy protein, containing multiple amino acids, is structurally similar to components of the extra-cellular matrix (ECM) of tissues. It is biological safety provided a good potential to be material for pure natural scaffolds. Moreover, as a protein, the properties of soy protein can be easily adjusted by modifying the functional groups on it. In addition, by blending soy protein with other synthetic and natural polymers, the mechanical characteristics and bioactive behavior of scaffolds can be facilitated for a variety of bio-applications. In this research, soy protein and polysaccharides tapioca starch are used, and gellan gum to develop a protein-based composite scaffold for cell engineering. The morphology and surface chemical composition are characterized via micro-computed tomography (micro-CT), scanning electron microscope (SEM), and fourier-transform infrared (FTIR) spectroscopy. The soy/tapioca/gellan gum (STG) composite scaffolds selectively help the adhesion and proliferation of L929 fibroblast cells while improving the migration of L929 fibroblast cells in STG composite scaffolds as the increase of soy protein proportion of the scaffold. In addition, STG composite scaffolds show great potential in the wound healing model to enhance rapid epithelialization and tissue granulation.

A universal strategy for the fabrication of single-photon and multiphoton NIR nanoparticles by loading organic dyes into water-soluble polymer nanosponges.

The development of optical organic nanoparticles (NPs) is desirable and widely studied. However, most organic dyes are water-insoluble such that the derivatization and modification of these dyes are difficult. Herein, we demonstrated a simple platform for the fabrication of organic NPs designed with emissive properties by loading ten different organic dyes (molar masses of 479.1-1081.7 g/mol) into water-soluble polymer nanosponges composed of poly(styrene-alt-maleic acid) (PSMA). The result showed a substantial improvement over the loading of commercial dyes (3.7-50% loading) while preventing their spontaneous aggregation in aqueous solutions. This packaging strategy includes our newly synthesized organic dyes (> 85% loading) designed for OPVs (242), DSSCs (YI-1, YI-3, YI-8), and OLEDs (ADF-1-3, and DTDPTID) applications. These low-cytotoxicity organic NPs exhibited tunable fluorescence from visible to near-infrared (NIR) emission for cellular imaging and biological tracking in vivo. Moreover, PSMA NPs loaded with designed NIR-dyes were fabricated, and photodynamic therapy with these dye-loaded PSMA NPs for the photolysis of cancer cells was achieved when coupled with 808 nm laser excitation. Indeed, our work demonstrates a facile approach for increasing the biocompatibility and stability of organic dyes by loading them into water-soluble polymer-based carriers, providing a new perspective of organic optoelectronic materials in biomedical theranostic applications.

Enhanced angiogenic potential of adipose-derived stem cell sheets by integration with cell spheroids of the same source.

BACKGROUND: Adipose-derived stem cell (ASC) has been considered as a desirable source for cell therapy. In contrast to combining scaffold materials with cells, ASCs can be fabricated into scaffold-free three-dimensional (3D) constructs to promote regeneration at tissue level. However, previous reports have found decreased expression of vascular endothelial growth factor (VEGF) in ASC sheets. In this study, we aimed to integrate ASC spheroids into ASC sheets to enhance the angiogenic capability of cell sheets. METHODS: ASCs were seeded in agarose microwells to generate uniform cell spheroids with adjustable size, while extracellular matrix deposition could be stimulated by ascorbic acid 2-phosphate to form ASC sheets. RNA sequencing was performed to identify the transcriptomic profiles of ASC spheroids and sheets relative to monolayer ASCs. By transferring ASC spheroids onto ASC sheets, the spheroid sheet composites could be successfully fabricated after a short-term co-culture, and their angiogenic potential was evaluated in vitro and in ovo. RESULTS: RNA sequencing analysis revealed that upregulation of angiogenesis-related genes was found only in ASC spheroids. The stimulating effect of spheroid formation on ASCs toward endothelial lineage was demonstrated by enhanced CD31 expression, which maintained after ASC spheroids were seeded on cell sheets. Relative to ASC sheets, enhanced expression of VEGF and hepatocyte growth factor was also noted in ASC spheroid sheets, and conditioned medium of ASC spheroid sheets significantly enhanced tube formation of endothelial cells in vitro. Moreover, chick embryo chorioallantoic membrane assay showed a significantly higher capillary density with more branch points after applying ASC spheroid sheets, and immunohistochemistry also revealed a significantly higher ratio of CD31-positive area. CONCLUSION: In the spheroid sheet construct, ASC spheroids can augment the pro-angiogenesis capability of ASC sheets without the use of exogenous biomaterial or genetic manipulation. The strategy of this composite system holds promise as an advance in 3D culture technique of ASCs for future application in angiogenesis and regeneration therapies.

A hemostatic keratin/alginate hydrogel scaffold with methylene blue mediated antimicrobial photodynamic therapy.

Uncontrollable bleeding and infection are two of the most common causes of trauma-related death. Yet, developing safe materials with high hemostatic and antibacterial effectiveness remains a challenge. Keratin-based biomaterials have been reported to exhibit the functions of enhancing platelet binding and activating and facilitating fibrinogen polymerization. In this study, we designed a hemostatic material with good biodegradability, biocompatibility, hemostatic ability, and antibacterial function to solve the shortcomings of common hemostatic materials. Methylene blue-loaded keratin/alginate composite scaffolds were prepared by the freeze-gelation method. The composite scaffolds exhibited over 1600% liquid absorption, well-interconnected pores, good biocompatibility, and biodegradability. We find that the keratin/alginate composite scaffolds' synergistic action may significantly reduce hemostasis time. To prevent infection, the drug-loaded scaffolds generated high burst release by absorbing wound exudate in the early stages of wound healing. The results obtained by the antimicrobial photoinactivation assay in vitro suggest that an antimicrobial photodynamic effect might be triggered, thereby preventing the fast growth of colonies.

Preparation of gamma poly-glutamic acid/hydroxyapatite/collagen composite as the 3D-printing scaffold for bone tissue engineering.

BACKGROUND: All types of movements involve the role of articular cartilage and bones. The presence of cartilage enables bones to move over one another smoothly. However, repetitive microtrauma and ischemia as well as genetic effects can cause an osteochondral lesion. Numerous treatment methods such as microfracture surgergy, autograft, and allograft, have been used, however, it possesses treatment challenges including prolonged recovery time after surgery and poses a financial burden on patients. Nowadays, various tissue engineering approaches have been developed to repair bone and osteochondral defects using biomaterial implants to induce the regeneration of stem cells.  METHODS: In this study, a collagen (Col)/γ-polyglutamate acid (PGA)/hydroxyapatite (HA) composite scaffold was fabricated using a 3D printing technique. A Col/γ-PGA/HA 2D membrane was also fabricated for comparison. The scaffolds (four layers) were designed with the size of 8 mm in diameter and 1.2 mm in thickness. The first layer was HA/γ-PGA and the second to fourth layers were Col/γ-PGA. In addition, a 2D membrane was constructed from hydroxyapatite/γ-PGA and collagen/γ-PGA with a ratio of 1:3. The biocompatibility property and degradation activity were investigated for both scaffold and membrane samples. Rat bone marrow mesenchymal stem cells (rBMSCs) and human adipose-derived stem cells (hADSCs) were cultured on the samples and were tested in-vitro to evaluate cell attachment, proliferation, and differentiation. In-vivo experiments were performed in the rat and nude mice models. RESULTS: In-vitro and in-vivo results show that the developed scaffold is of well biodegradation and biocompatible properties, and the Col-HA scaffold enhances the mechanical properties for osteochondrogenesis in both in-vitro and animal trials. CONCLUSIONS: The composite would be a great biomaterial application for bone and osteochondral regeneration.

Design and Synthesis of Stem Cell-Laden Keratin/Glycol Chitosan Methacrylate Bioinks for 3D Bioprinting.

With the advancements in tissue engineering and three-dimensional (3D) bioprinting, physiologically relevant three-dimensional structures with suitable mechanical and bioactive properties that mimic the biological tissue can be designed and fabricated. However, the available bioinks are less than demanded. In this research, the readily available biomass sources, keratin and glycol chitosan, were selected to develop a UV-curable hydrogel that is feasible for the 3D bioprinting process. Keratin methacrylate and glycol chitosan methacrylate were synthesized, and a hybrid bioink was created by combining this protein-polysaccharide cross-linked hydrogel. While human hair keratin could provide biological functions, the other composition, glycol chitosan, could further enhance the mechanical strength of the construct. The mechanical properties, degradation profile, swelling behavior, cell viability, and proliferation were investigated with various ratios of keratin methacrylate to glycol chitosan methacrylate. The composition of 2% (w/v) keratin methacrylate and 2% (w/v) chitosan methacrylate showed a significantly higher cell number and swelling percentage than other compositions and was designated as the bioink for 3D printing afterward. The feasibility of stem cell loading in the selected formula was examined with an extrusion-based bioprinter. The cells and spheroids can be successfully printed with the synthesized bioink into a specific shape and cultured. This work provides a potential option for bioinks and delivers insights into personalization research on stem cell-laden biofabricated hydrogels in the future.

Glycol chitosan/iron oxide/polypyrrole nanoclusters for precise chemodynamic/photothermal synergistic therapy.

Noninvasive photothermal therapy (PTT) represents a promising direction for more modern and precise medical applications. However, PTT efficacy is still not satisfactory due to the existence of heat shock proteins (HSPs) and poorly targeted delivery. Herein, the design of a nanosystem with improved delivery efficacy for anticancer treatment employing the synergetic effects of reactive oxygen species (ROS)-driven chemodynamic therapy (CDT) to inactivated HSPs with photothermal-hyperthermia was therefore achieved through the development of pH-targeting glycol chitosan/iron oxide enclosed core polypyrrole nanoclusters (GCPI NCs). The designed NCs effectively accumulated toward cancer cells due to their acidic microenvironment, initiating ROS generation via Fenton reaction at the outset and performing site-specific near infrared (NIR)-photothermal effect. A comprehensive analysis of both surface and bulk material properties of the CDT/PTT NCs as well as biointerface properties were ascertained via numerous surface specific analytical techniques by bringing together heightened accumulation of CDT/PTT NCs, which can significantly eradicate cancer cells thus minimizing the side effects of conventional chemotherapies. All of these attributes act in synergy over the cancer cells succeeding in fashioning NC's able to act as competent agents in the MRI-monitored enhanced CDT/PTT synergistic therapy. Findings in this study evoke attention in future oncological therapeutic strategies.

Enhancing Stability of High-Concentration ß-Tricalcium Phosphate Suspension for Biomedical Application.

We propose a novel process to efficiently prepare highly dispersed and stable Tricalcium Phosphate (ß-TCP) suspensions. TCP is coupled with a polymer to enhance its brittleness to be used as an artificial hard tissue. A high solid fraction of ß-TCP is mixed with the polymer in order to improve the mechanical strength of the prepared material. The high solid fractions led to fast particle aggregation due to Van der Waals forces, and sediments appeared quickly in the suspension. As a result, we used a dispersant, dispex AA4040 (A40), to boost the surface potential and steric hindrance of particles to make a stable suspension. However, the particle size of ß-TCP is too large to form a suspension, as the gravity effect is much more dominant than Brownian motion. Hence, ß-TCP was subjected to wet ball milling to break the aggregated particles, and particle size was reduced to ~300 nm. Further, to decrease sedimentation velocity, cellulose nanocrystals (CNCs) are added as a thickening agent to increase the overall viscosity of suspension. Besides the viscosity enhancement, CNCs were also wrapped with A40 micelles and increase the stability of the suspension. These CNC/A40 micelles further facilitated stable suspension of ß-TCP particles with an average hydration radius of 244.5 nm. Finally, ß-TCP bone cement was formulated with the suspension, and the related cytotoxicity was estimated to demonstrate its applicability for hard tissue applications.

Rational design of a highly porous electronic scaffold with concurrent enhancement in cell behaviors and differentiation under electrical stimulation.

Conductive polymers (CPs) have received increasing attention as promising materials for studying electrophysiological signals in cell and tissue engineering. The combination of CPs with electrical stimulation (ES) could possibly enhance neurogenesis, osteogenesis, and myogenesis. To date, research has been prioritized on capitalizing CPs as two-dimensional (2D) structures for guiding the differentiation. In contrast, relatively little is conducted on the implementation of 3D conductive scaffolds. In this research, we report the synergic assembly of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and multi-walled carbon nanotubes (MWCNTs) as a biocompatible, electrically conductive, mechanically robust and structurally porous 3D scaffold. To showcase the bioelectronic utilization, a proof-of-concept demonstration of electrically stimulated cell culture under ES is conducted. The ES effects coupled with the 3D scaffold are promising on pheochromocytoma 12 (PC12), a neuronal cell line, and the ES effect on osteogenesis of human adipose-derived stem cells (hASC) was further studied. PC12 cultured on this PEDOT:PSS/MWCNT 3D scaffolds was induced to differentiate toward a more mature neuronal phenotype with the ES treatment. Furthermore, hASC osteogenesis could be highly promoted in this conductive scaffold with ES. Calcium deposition concentration and osteo-differentiated gene markers were significantly higher with ES. The facile assembly of 3D conductive scaffolds sheds light on both platforms for investigating the 3D microenvironment for electrophysiological simulation of cells and tissues under the ES treatment of in vivo tissue engineering.