Self-Assembled Food Peptides: Recent Advances and Perspectives in Food and Health Applications.

Self-assembling peptides are rapidly gaining attention as novel biomaterials for food and biomedical applications. Peptides self-assemble when triggered by physical or chemical factors due to their versatile physicochemical characteristics. Peptide self-assembly, when combined with the health-promoting bioactivity of peptides, can also result in a plethora of biofunctionalities of the biomaterials. This perspective highlights current developments in the use of food-derived self-assembling peptides as biomaterials, bioactive nutraceuticals, and potential dual functioning bioactive biomaterials. Also discussed are the challenges and opportunities in the use of self-assembling bioactive peptides in designing biocompatible, biostable, and bioavailable multipurpose biomaterials.

Tetramethylpyrazine-loaded electroconductive hydrogels promote tissue repair after spinal cord injury by protecting the blood-spinal cord barrier and neurons.

Spinal cord injury (SCI) usually induces profound microvascular dysfunction. It disrupts the integrity of the blood-spinal cord barrier (BSCB), which could trigger a cascade of secondary pathological events that manifest as neuronal apoptosis and axonal demyelination. These events can further lead to irreversible neurological impairments. Thus, reducing the permeability of the BSCB and maintaining its substructural integrity are essential to promote neuronal survival following SCI. Tetramethylpyrazine (TMP) has emerged as a potential protective agent for treating the BSCB after SCI. However, its therapeutic potential is hindered by challenges in the administration route and suboptimal bioavailability, leading to attenuated clinical outcomes. To address this challenge, traditional Chinese medicine, TMP, was used in this study to construct a drug-loaded electroconductive hydrogel for synergistic treatment of SCI. A conductive hydrogel combined with TMP demonstrates good electrical and mechanical properties as well as superior biocompatibility. Furthermore, it also facilitates sustained local release of TMP at the implantation site. Furthermore, the TMP-loaded electroconductive hydrogel could suppress oxidative stress responses, thereby diminishing endothelial cell apoptosis and the breakdown of tight junction proteins. This concerted action repairs BSCB integrity. Concurrently, myelin-associated axons and neurons are protected against death, which meaningfully restore neurological functions post spinal cord injury. Hence, these findings indicate that combining the electroconductive hydrogel with TMP presents a promising avenue for potentiating drug efficacy and synergistic repair following SCI.

Laser-Synthesized Germanium Nanoparticles as Biodegradable Material for Near-Infrared Photoacoustic Imaging and Cancer Phototherapy.

Biodegradable nanomaterials can significantly improve the safety profile of nanomedicine. Germanium nanoparticles (Ge NPs) with a safe biodegradation pathway are developed as efficient photothermal converters for biomedical applications. Ge NPs synthesized by femtosecond-laser ablation in liquids rapidly dissolve in physiological-like environment through the oxidation mechanism. The biodegradation of Ge nanoparticles is preserved in tumor cells in vitro and in normal tissues in mice with a half-life as short as 3.5 days. Biocompatibility of Ge NPs is confirmed in vivo by hematological, biochemical, and histological analyses. Strong optical absorption of Ge in the near-infrared spectral range enables photothermal treatment of engrafted tumors in vivo, following intravenous injection of Ge NPs. The photothermal therapy results in a 3.9-fold reduction of the EMT6/P adenocarcinoma tumor growth with significant prolongation of the mice survival. Excellent mass-extinction of Ge NPs (7.9 L g-1 cm-1 at 808 nm) enables photoacoustic imaging of bones and tumors, following intravenous and intratumoral administrations of the nanomaterial. As such, strongly absorbing near-infrared-light biodegradable Ge nanomaterial holds promise for advanced theranostics.

External stimuli-triggered photodynamic and sonodynamic therapies in combination with hybrid nanomicelles of ICG@PEP@HA: laser vs. ultrasound.

The concept of combining external medical stimuli with internal functional biomaterials to achieve cancer-oriented treatments is being emergingly developed. Optical and acoustical activations have shown particular promise as non-invasive regulation modalities in cancer treatment and intervention. It is always challenging to leverage the contributions of optical and acoustical stimuli and find appropriate biomaterials to optimally match them. Herein, a type of hybrid nanomicelle (ICG@PEP@HA) containing ICG as a photo/sonosensitizer, an amphiphilic peptide for membrane penetration and hyaluronic acid for cluster determinant 44 (CD44) targeting was fabricated. Triggered by the external stimuli of laser and US irradiation, their photo/sonothermal performance, in vitro reactive oxygen species (ROS) production capability and tumor-targeting efficiency have been systematically evaluated. It was interestingly found that the external stimulus of laser irradiation induced a greater quantity of ROS, which resulted in significant cell apoptosis and tumor growth inhibition in the presence of ICG@PEP@HA. The individual analyses and corresponding rationales have been investigated. Meanwhile, these hybrid nanomicelles were administered into MDA-MB-231 tumor-bearing nude mice for PDT and SDT therapies and their biocompatibility assessment, and a prevailing PDT efficacy and reliable bio-safety have been evidenced based on the hematological analysis and histochemical staining. In summary, this study has validated a novel pathway to utilize these hybrid nanomicelles for laser/US-triggered localized tumor treatment, and the treatment efficiency may be leveraged by different external stimuli sources. It is also expected to give rise to full accessibility to clinical translations for human cancer treatments by means of the as-reported laser/US-nanomicelle combination strategy.

New approaches to second-degree burn healing: Polyvinyl alcohol membrane loaded to arnica combined to laser therapy.

Second-degree burns require greater care, as the damage is more extensive and worrisome and the use of a biomaterial can help in the cell repair process, with better planning, low cost, and better accessibility. Arnica has anti-inflammatory and analgesic properties in skin lesions treatments and laser therapy is another therapeutic alternative for burns. Evaluate the effects of arnica incorporated into PVA associated or not with low intensity laser on burns in rats. PVA and PVA with arnica (PVA+A) were obtained and characterized physicochemically. Through in vivo studies, the effects of PVA and PVA+A with or without the application of laser on the lesions allowed histological and immunohistochemical analyzes. PVA+A was biocompatible and with sustained release of the active, being a promising pharmacological tool and confirmed that laser therapy was effective in accelerating the healing process, due to its potential biomodulator, improving inflammatory aspects, promoting rapid healing in skin lesions.

Multifunctional biomimetic hydrogel dressing provides anti-infection treatment and improves immunotherapy by reprogramming the infection-related wound microenvironment.

The advancement of biomaterials with antimicrobial and wound healing properties continues to present challenges. Macrophages are recognized for their significant role in the repair of infection-related wounds. However, the interaction between biomaterials and macrophages remains complex and requires further investigation. In this research, we propose a new sequential immunomodulation method to enhance and expedite wound healing by leveraging the immune properties of bacteria-related wounds, utilizing a novel mixed hydrogel dressing. The hydrogel matrix is derived from porcine acellular dermal matrix (PADM) and is loaded with a new type of bioactive glass nanoparticles (MBG) doped with magnesium (Mg-MBG) and loaded with Curcumin (Cur). This hybrid hydrogel demonstrates controlled release of Cur, effectively eradicating bacterial infection in the early stage of wound infection, and the subsequent release of Mg ions (Mg2+) synergistically inhibits the activation of inflammation-related pathways (such as MAPK pathway, NF-κB pathway, TNF-α pathway, etc.), suppressing the inflammatory response caused by infection. Therefore, this innovative hydrogel can safely and effectively expedite wound healing during infection. Our design strategy explores novel immunomodulatory biomaterials, offering a fresh approach to tackle current clinical challenges associated with wound infection treatment.

From Basic Principles of Protein-Polysaccharide Association to the Rational Design of Thermally Sensitive Materials.

Biology resolves design requirements toward functional materials by creating nanostructured composites, where individual components are combined to maximize the macroscale material performance. A major challenge in utilizing such design principles is the trade-off between the preservation of individual component properties and emerging composite functionalities. Here, polysaccharide pectin and silk fibroin were investigated in their composite form with pectin as a thermal-responsive ion conductor and fibroin with exceptional mechanical strength. We show that segregative phase separation occurs upon mixing, and within a limited compositional range, domains ∼50 nm in size are formed and distributed homogeneously so that decent matrix collective properties are established. The composite is characterized by slight conformational changes in the silk domains, sequestering the hydrogen-bonded ß-sheets as well as the emergence of randomized pectin orientations. However, most dominant in the composite's properties is the introduction of dense domain interfaces, leading to increased hydration, surface hydrophilicity, and increased strain of the composite material. Using controlled surface charging in X-ray photoelectron spectroscopy, we further demonstrate Ca ions (Ca2+) diffusion in the pectin domains, with which the fingerprints of interactions at domain interfaces are revealed. Both the thermal response and the electrical conductance were found to be strongly dependent on the degree of composite hydration. Our results provide a fundamental understanding of the role of interfacial interactions and their potential applications in the design of material properties, polysaccharide-protein composites in particular.

Bionic Bilayer Scaffold for Synchronous Hyperthermia Therapy of Orthotopic Osteosarcoma and Osteochondral Regeneration.

Large osseous void, postsurgical neoplastic recurrence, and slow bone-cartilage repair rate raise an imperative need to develop functional scaffold in clinical osteosarcoma treatment. Herein, a bionic bilayer scaffold constituting croconaine dye-polyethylene glycol@sodium alginate hydrogel and poly(l-lactide)/hydroxyapatite polymer matrix is fabricated to simultaneously achieve a highly efficient killing of osteosarcoma and an accelerated osteochondral regeneration. First, biomimetic osteochondral structure along with adequate interfacial interaction of the bilayer scaffold provide a structural reinforcement for transverse osseointegration and osteochondral regeneration, as evidenced by upregulated specific expressions of collagen type-I, osteopontin, and runt-related transcription factor 2. Meanwhile, thermal ablation of the synthesized nanoparticles and mitochondrial dysfunction caused by continuously released hydroxyapatite induce residual tumor necrosis synergistically. To validate the capabilities of inhibiting tumor growth and promoting osteochondral regeneration of our proposed scaffold, a novel orthotopic osteosarcoma model simulating clinical treatment scenarios of bone tumors is established on rats. Based on amounts of in vitro and in vivo results, an effective killing of osteosarcoma and a suitable osteal-microenvironment modulation of such bionic bilayer composite scaffold are achieved, which provides insightful implications for photonic hyperthermia therapy against osteosarcoma and following osseous tissue regeneration.

In vitro assessment of Momordica charantia/Hypericum perforatum oils loaded PCL/Collagen fibers: Novel scaffold for tissue engineering.

The research on tissue engineering applications has been progressing to manufacture ideal tissue scaffold biomaterials. In this study, a double-layered electrospun biofiber scaffold biomaterial including Polycaprolactone (PCL)/Collagen (COL) fibrous inner layer and PCL/ Momordica charantia (MC) and Hypericum perforatum (HP) oils fibrous outer layer was developed to manufacture a functional, novel tissue scaffold with the advantageous mechanical and biological properties. The main approach was to combine the natural perspective using medicinal oils with an engineering point of view to fabricate a potential functional scaffold for tissue engineering. Medicinal plants MC and HP are rich in functional oils and incorporation of them in a tissue scaffold will unveil their potential to augment both new tissue formation and wound healing. In this study, a novel double-layered scaffold prototype was fabricated using electrospinning technique with two PCL fiber layers, first is composed of collagen, and second is composed of oils extracted from medicinal plants. Initially, the composition of plant oils was analyzed. Thereafter the biofiber scaffold layers were fabricated and were evaluated in terms of morphology, physicochemistry, thermal and mechanical features, wettability, in vitro bio-degradability. Double-layered scaffold prototype was further analyzed in terms of in vitro biocompatibility and antibacterial effect. The medicinal oils blend provided antioxidant and antibacterial properties to the novel PCL/Oils layer. The results signify that inner PCL/COL layer exhibited advanced biodegradability of 8.5% compared to PCL and enhanced wettability with 11.7° contact angle. Strength of scaffold prototype was 5.98 N/mm2 thanks to the elastic PCL fibrous matrix. The double-layered functional biofiber scaffold enabled 92% viability after 72 h contact with fibroblast cells and furthermore provided feasible attachment sites for the cells. The functional scaffold prototype's noteworthy mechanical, chemical, and biological features enable it to be suggested as a different novel biomaterial with the potential to be utilized in tissue engineering applications.

Sandwich hydrogel to realize cartilage-mimetic structures and performances from polyvinyl alcohol, chitosan and sodium hyaluronate.

Developing artificial substitutes that mimic the structures and performances of natural cartilage is of great importance. However, it is challenging to integrate the high strength, excellent biocompatibility, low coefficient of friction, long-term wear resistance, outstanding swelling resistance, and osseointegration potential into one material. Herein, a sandwich hydrogel with cartilage-mimetic structures and performances was prepared to achieve this goal. The precursor hydrogel was obtained by freezing-thawing the mixture of poly vinyl alcohol, chitosan and deionized water three cycles, accompanied by soaking in sodium hyaluronate solution. The top of the precursor hydrogel was hydrophobically modified with lauroyl chloride and then loaded with lecithin, while the bottom was mineralized with hydroxyapatite. Due to the multiple linkages (crystalline domains, hydrogen bonds, and ionic interactions), the compressive stress was 71 MPa. Owing to the synergy of the hydrophobic modification and lecithin, the coefficient of friction was 0.01. Additionally, no wear trace was observed after 50,000 wear cycles. Remarkably, hydroxyapatite enabled the hydrogel osseointegration potential. The swelling ratio of the hydrogel was 0.06 g/g after soaking in simulated synovial fluid for 7 days. Since raw materials were non-toxic, the cell viability was 100 %. All of the above merits make it an ideal material for cartilage replacement.

Magnetic and injectable Fe-doped liquid metals for controlled movement and photothermal/electromagnetic therapy.

As a multifunctional material, gallium-based liquid metal (LM) mixtures with metal particles dispersed in the LM environment display many excellent and intriguing properties. In this study, biomaterials were prepared by mixing Fe particles with LM for easily manageable photothermal or electromagnetic therapy and evaluated. Clinically, the fabricated 5%Fe/LM sample was injectable and radiopaque, which allowed its smooth delivery through a syringe to the target tissues, where it could help achieve clear imaging under CT. Meanwhile, because of the loading of Fe particles, the 5%Fe/LM possessed a magnetic property, implying a high manipulation capability. According to the experiments, the capsule containing 5%Fe/LM when placed in an isolated pig large intestine could move as desired to the designated position through an external magnet. Further, the biosafety and low toxicity of the 5%Fe/LM were confirmed by cytotoxicity tests in vitro, and the temperature changes at the interface between the 5%Fe/LM and intestinal tissue after near-infrared (NIR) laser irradiation were determined through theoretical modeling and numerical simulation data analysis. Due to the excellent photothermal and magnetothermal effects of LM, the temperature of the 5%Fe/LM injected into the rabbit abdominal cavity could significantly increase under NIR laser or alternating magnetic field (AMF) administration. As a novel functional biomaterial, the 5%Fe/LM exhibited promising potential for designated position movement and photothermal or magnetothermal therapy in the near future.

A microscale 3D organ on a chip for recapitulating reciprocal neuroendocrine crosstalk between the hypothalamus and the pituitary gland.

Conventional 2D or even recently developed 3Din vitroculture models for hypothalamus and pituitary gland cannot successfully recapitulate reciprocal neuroendocrine communications between these two pivotal neuroendocrine tissues known to play an essential role in controlling the body's endocrine system, survival, and reproduction. In addition, most currentvitroculture models for neuroendocrine tissues fail to properly reflect their complex multicellular structure. In this context, we developed a novel microscale chip platform, termed the 'hypothalamic-pituitary (HP) axis-on-a-chip,' which integrates various cellular components of the hypothalamus and pituitary gland with biomaterials such as collagen and hyaluronic acid. We used non-toxic blood coagulation factors (fibrinogen and thrombin) as natural cross-linking agents to increase the mechanical strength of biomaterials without showing residual toxicity to overcome drawbacks of conventional chemical cross-linking agents. Furthermore, we identified and verified SERPINB2 as a reliable neuroendocrine toxic marker, with its expression significantly increased in both hypothalamus and pituitary gland cells following exposure to various types of toxins. Next, we introduced SERPINB2-fluorescence reporter system into loaded hypothalamic cells and pituitary gland cells within each chamber of the HP axis on a chip, respectively. By incorporating this SERPINB2 detection system into the loaded hypothalamic and pituitary gland cells within our chip platform, Our HP axis-on-chip platform can better mimic reciprocal neuroendocrine crosstalk between the hypothalamus and the pituitary gland in the brain microenvironments with improved efficiency in evaluating neuroendocrine toxicities of certain drug candidates.

Incorporation of black phosphorus nanosheets into poly(propylene fumarate) biodegradable bone cement to enhance bioactivity and osteogenesis.

BACKGROUND: Injectable bone cement is commonly used in clinical orthopaedics to fill bone defects, treat vertebral compression fractures, and fix joint prostheses during joint replacement surgery. Poly(propylene fumarate) (PPF) has been proposed as a biodegradable and injectable alternative to polymethylmethacrylate (PMMA) bone cement. Recently, there has been considerable interest in two-dimensional (2D) black phosphorus nanomaterials (BPNSs) in the biomedical field due to their excellent photothermal and osteogenic properties. In this study, we investigated the biological and physicochemical qualities of BPNSs mixed with PPF bone cement created through thermal cross-linking. METHODS: PPF was prepared through a two-step process, and BPNSs were prepared via a liquid phase stripping method. BP/PPF was subsequently prepared through thermal cross-linking, and its characteristics were thoroughly analysed. The mechanical properties, cytocompatibility, osteogenic performance, degradation performance, photothermal performance, and in vivo toxicity of BP/PPF were evaluated. RESULTS: BP/PPF exhibited low cytotoxicity levels and mechanical properties similar to that of bone, whereas the inclusion of BPNSs promoted preosteoblast adherence, proliferation, and differentiation on the surface of the bone cement. Furthermore, 200 BP/PPF demonstrated superior cytocompatibility and osteogenic effects, leading to the degradation of PPF bone cement and enabling it to possess photothermal properties. When exposed to an 808-nm laser, the temperature of the bone cement increased to 45-55 °C. Furthermore, haematoxylin and eosin-stained sections from the in vivo toxicity test did not display any anomalous tissue changes. CONCLUSION: BP/PPF exhibited mechanical properties similar to that of bone: outstanding photothermal properties, cytocompatibility, and osteoinductivity. BP/PPF serves as an effective degradable bone cement and holds great potential in the field of bone regeneration.

Maximizing crustaceans (shrimp, crab, and lobster) by-products value for optimum valorization practices: A comparative review of their active ingredients, extraction, bioprocesses and applications.

BACKGROUND: The processing of the three major crustaceans (shrimp, lobster, and crab) is associated with inevitable by-products, high waste disposal costs, environmental and human health issues, loss of multiple biomaterials (chitin, protein hydrolysates, lipids, astaxanthin and minerals). Nowadays, these bioresources are underutilized owing to the lack of effective and standardized technologies to convert these materials into valued industrial forms. AIM OF REVIEW: This review aims to provide a holistic overview of the various bioactive ingredients and applications within major crustaceans by-products. This review aims to compare various extraction methods in crustaceans by-products, which will aid identify a more workable platform to minimize waste disposal and maximize its value for best valorization practices. KEY SCIENTIFIC CONCEPTS OF REVIEW: The fully integrated applications (agriculture, food, cosmetics, pharmaceuticals, paper industries, etc.) of multiple biomaterials from crustaceans by-products are presented. The pros and cons of the various extraction methods, including chemical (acid and alkali), bioprocesses (enzymatic or fermentation), physical (microwave, ultrasound, hot water and carbonic acid process), solvent (ionic liquids, deep eutectic solvents, EDTA) and electrochemistry are detailed. The rapid development of corresponding biotechnological attempts present a simple, fast, effective, clean, and controllable bioprocess for the comprehensive utilization of crustacean waste that has yet to be applied at an industrial level. One feasible way for best valorization practices is to combine innovative extraction techniques with industrially applicable technologies to efficiently recover these valuable components.

Using osteogenic medium in the in vitro evaluation of bone biomaterials: Artefacts due to a synergistic effect.

In vitro tests using bone cells to evaluate the osteogenic potential of biomaterials usually employ the osteogenic medium (OM). The lack of correlation frequently reported between in vitro and in vivo studies in bone biomaterials, makes necessary the evaluation of the impact of osteogenic supplements on these results. This study analysed the proteomic profiles of human osteoblasts (HOb) cultured in the media with and without osteogenic agents (ascorbic acid and ß-glycerol phosphate). The cells were incubated for 1 and 7 days, on their own or in contact with Ti. The comparative Perseus analysis identified 2544 proteins whose expression was affected by osteogenic agents. We observed that the OM strongly alters protein expression profiles with a complex impact on multiple pathways associated with adhesion, immunity, oxidative stress, coagulation, angiogenesis and osteogenesis. OM-triggered changes in the HOb intracellular energy production mechanisms, with key roles in osteoblast maturation. HOb cultured with and without Ti showed enrichment in the skeletal system development function due to the OM. However, differentially expressed proteins with key regenerative functions were associated with a synergistic effect of OM and Ti. This synergy, caused by the Ti-OM interaction, could complicate the interpretation of in vitro results, highlighting the need to analyse this phenomenon in biomaterial testing.

Sprayable tissue adhesive microparticle-magnetic nanoparticle composites for local cancer hyperthermia.

Incomplete removal of early-stage gastrointestinal cancers by endoscopic treatments often leads to recurrence induced by residual cancer cells. To completely remove or kill cancer tissues and cells and prevent recurrence, chemotherapy, radiotherapy, and hyperthermia using biomaterials with drugs or nanomaterials are usually administered following endoscopic treatments. However, there are few biomaterials that can be applied using endoscopic devices to locally kill cancer tissues and cells. We previously reported that decyl group-modified Alaska pollock gelatin-based microparticles (denoted C10MPs) can adhere to gastrointestinal tissues under wet conditions through the formation of a colloidal gel driven by hydrophobic interactions. In this study, we combined C10MPs with superparamagnetic iron oxide nanoparticles (SPIONs) to develop a sprayable heat-generating nanomaterial (denoted SP/C10MP) for local hyperthermia of gastrointestinal cancers. The rheological property, tissue adhesion strength, burst strength, and underwater stability of SP/C10MP were improved through decyl group modification and SPION addition. Moreover, SP/C10MP that adhered to gastrointestinal tissues formed a colloidal gel, which locally generated heat in response to an alternating magnetic field. SP/C10MP successfully killed cancer tissues and cells in colon cancer-bearing mouse models in vitro and in vivo. Therefore, SP/C10MP has the potential to locally kill residual cancer tissues and cells after endoscopic treatments.

Extraction, purification, characteristics, bioactivities, prospects, and toxicity of Lilium spp. polysaccharides.

The genus Lilium has been widely used worldwide as a food and medicinal ingredient in East Asia for over 2000 years due to its higher nutritional and medicinal value. Polysaccharide is the most important bioactive ingredient in Lilium spp. and has various health benefits. Recently, Lilium spp. polysaccharides (LSPs) have attracted significant attention from industries and researchers due to their various biological properties, such as antioxidant, immunomodulatory, antitumor, antibacterial, hypoglycaemic, and anti-radiation. However, the development and utilization of LSP-based functional biomaterials and medicines are limited by a lack of comprehensive understanding regarding the structure-activity relationships (SARs), industrial applications, and safety of LSPs. This review provides an inclusive overview of the extraction, purification, structural features, bioactivities, and mechanisms of LSPs. SARs, applications, toxicities, and influences of structural modifications on bioactivities are also highlighted, and the potential development and future study direction are scrutinized. This article aims to offer a complete understanding of LSPs and provide a foundation for further research and application of LSPs as therapeutic agents and multifunctional biomaterials.

Recent progress and treatment strategy of pectin polysaccharide based tissue engineering scaffolds in cancer therapy, wound healing and cartilage regeneration.

Natural polymers and its mixtures in the form of films, sponges and hydrogels are playing a major role in tissue engineering and regenerative medicine. Hydrogels have been extensively investigated as standalone materials for drug delivery purposes as they enable effective encapsulation and sustained release of drugs. Biopolymers are widely utilised in the fabrication of hydrogels due to their safety, biocompatibility, low toxicity, and regulated breakdown by human enzymes. Among all the biopolymers, polysaccharide-based polymer is well suited to overcome the limitations of traditional wound dressing materials. Pectin is a polysaccharide which can be extracted from different plant sources and is used in various pharmaceutical and biomedical applications including cartilage regeneration. Pectin itself cannot be employed as scaffolds for tissue engineering since it decomposes quickly. This article discusses recent research and developments on pectin polysaccharide, including its types, origins, applications, and potential demands for use in AI-mediated scaffolds. It also covers the materials-design process, strategy for implementation to material selection and fabrication methods for evaluation. Finally, we discuss unmet requirements and current obstacles in the development of optimal materials for wound healing and bone-tissue regeneration, as well as emerging strategies in the field.

Route-dependent tailoring of carbon dot release in alginate hydrogel beads (HB-Alg@WTR-CDs): A versatile platform for biomedical applications.

The present investigation explores the different pathways for development of waste tea residue carbon dots (WTR-CDs) loading into hydrogel matrix for WTR-CDs releasing probe. Fluorescent WTR-CDs incorporated into hydrogel matrix were synthesized by valorisation of kitchen waste tea by simple carbonization method (λem = 450 nm, ΦWTR-CDs =18.45 %). Biopolymeric alginate-based hydrogel beads (HB-Alg) were prepared by simple extrusion method. Three routes (ex-situ/in-situ) were employed for loading of WTR-CDs into hydrogel matrix. Successful synthesis of WTR-CDs and its loading into hydrogel matrix was confirmed via various characterization techniques. Developed protocol was employed for stimuli-responsive cumulative release of WTR-CDs study (pH = 3.0, 7.4, 9.0) was monitored over 7 days. Results suggests that, the HB-Alg@WTR-CDs-A system with in-situ loaded WTR-CDs have sustained release due to ionic interaction of WTR-CDs with crosslinked polymer network, whereas in HB-Alg@WTR-CDs-B, WTR-CDs loaded in wet-beads having burst release in which loosely bound WTR-CDs into hydrogel cavities releases rapidly. While, in case of HB-Alg@WTR-CDs-C, lowest release was observed due to weakly surface bound WTR-CDs, low loading and shrinkage of pores into dry-beads. Radical scavenging activity was studied and shown antioxidant properties of WTR-Powder, WTR-CDs and HB-Alg@WTR-CDs-A,B,C. Cytotoxicity of all systems was checked via CAM assay and significant growth in blood vascularization with no loss of chick embryo confirming the released WTR-CDs are biocompatible. Successful investigation and summarization of results ensure that, waste-valorisation, simple, sustainable, and smart hydrogel systems with different routes of WTR-CDs loading have opened a window to understand the mechanistic pathways in release behaviour. This robust approach for improvement of smarter and biocompatible materials can be fruitfully applicable in advanced, controlled and stimuli responsive delivery probes.

Porous scaffold hydroxyapatite from sand lobster shells (Panulirus homarus) using polyethylene oxide/chitosan as polymeric porogen for bone tissue engineering.

The hydroxyapatite (HAp; Ca10 (PO4 )6 (OH)2 )) has good biocompatibility, bioactivity, and osteoconductivity as a bone implant because the main inorganic mineral of human bone is HAp. The use of scaffold HAp from biogenic resources that contain high calcium and polymer as a pore forming agent to support bone growth is a longstanding area of interest. In this study, porous scaffolds based on HAp were synthesized from sand lobster (SL; Panulirus homarus) shells as a source of calcium using the porogen leaching method with polyethylene oxide (PEO) and chitosan (Chs) as polymeric porogen. The present study aims to synthesize HAp derived from SL shells and evaluate the effect variations of PEO on the physicochemical properties of the scaffold and cytotoxicity in cell viability assay. Briefly, the SL shell powder was calcinated with temperature variations of 600°C, 800°C, and 1000°C for 6 h. Based on the characterization, it was shown that 1000°C was the optimum calcination temperature for SL shells to synthesize HAp using the precipitation method. The characterization results of HAp using energy dispersive x-ray (EDX) revealed that the molar ratio of Ca/P was 1.67. The Fourier transform infrared (FTIR) and x-ray diffractometer (XRD) spectral patterns indicated that HAp had been successfully synthesized with minor ß-tricalcium phosphate (ß-TCP), a calcium phosphate with high biocompatibility. Porous scaffolds were synthesized by varying the concentration of PEO at 0, 5, 10, and 15 wt %. Physicochemical analysis revealed that a higher concentration of PEO affected decreased crystallinity and compressive strength, but on the other hand, the porosity and pore sizes increased. Based on the physicochemical analysis, the synthesized porous scaffold showed that HAp/PEO/Chs 15 wt % had the most potential as a scaffold for biomedical applications. MTT Assay, after 24 h incubation, revealed that the scaffold was safe for use at low concentrations on the MC3T3E1 osteoblast cells, with a percentage of cell viability of 83.23 ± 3.18% at 23.4375 µg/mL. Although the cell viability decreased at higher concentrations, the HAp/PEO/Chs 15 wt % scaffold was cytocompatible with the cells. Thus, in the present study, HAp/PEO/Chs 15 wt % was the best scaffold based on pore structure, chemical composition, mechanical and crystalographic properties and cell viability.