Designing Biomaterials for Regenerative Medicine: State-of-the-Art and Future Perspectives
Naznin Sultana, Sanchita Bandyopadhyay-Ghosh, Chin Fhong Soon in Tissue Engineering Strategies for Organ Regeneration, 2020
The synthetic biodegradable polymers are major groups of polymers that are popular in tissue engineering. These biodegradable and noncytotoxic materials can support cell attachment, proliferation and differentiation to reconstruct tissue defect (Guelcher 2008). A major difference between natural biopolymers and synthetic polymers is in their structures. Most synthetic polymers have much simpler than natural polymer structures. The degradation rate of these groups of materials are adjustable by changing the mixing ratio, molecular weight of components and other parameters to match with the regeneration rate of the tissue. Polyanhydrides, polyesters, polyphosphazenes, poly (glycerol sebacate) and polyurethanes are classified in this group of materials. This group can be manipulated to the desirable characteristics. Since polyanhydrides possess high hydrophobicity and favorable degradation pattern (degradation from the surface to the inside), they are appropriate for drug-delivery applications (Jain et al. 2008).
Nanosuspensions as Nanomedicine: Current Status and Future Prospects
Debarshi Kar Mahapatra, Sanjay Kumar Bharti in Medicinal Chemistry with Pharmaceutical Product Development, 2019
Apart from these, D-α-tocopherol polyethylene glycol 1000 succinate (TPGS), polyethylene glycols (PEGs), polyvinyl alcohols (PVAs) have also been used as stabilizers [70]. However, the nanosuspensions are not stabilized permanently by these stabilizers and aggregation may occur during storage or when nanosuspensions are being dried. Furthermore, some of the common stabilizers raise toxicity concerns if used in large quantity for a long-term, limiting the therapeutic application of drug nanosuspensions [4, 71–74]. For example, Cremophor® EL and Tween–80 are two commercial surfactants that are widely used to solubilize poorly water-soluble drugs, but they also cause serious neuro-and nephrotoxicity as well as acute hypersensitivity reaction [75, 76]. Thus, there remains to be a demand to find new stabilizers with better stabilizing capacity and less toxicity. Food biopolymers, especially food proteins, are widely used in formulated foods because they have high nutritional values and are generally recognized as safe [77, 78]. The proteins include soybean protein isolate (SPI), whey protein isolate (WPI), β-lactoglobulin (β-lg), etc. (Table 4.1). The drug-to-stabilizer ratio in the formulation may vary from 1:20 to 20:1 and should be investigated in specific case(s). Lecithin is the stabilizer of choice if one intends to develop a parenteral nanosuspension [22].
Three-dimensional scaffold in bone regeneration
R.M. Natal Jorge, J.C. Reis Campos, Mário A.P. Vaz, Sónia M. Santos, João Manuel R.S. Tavares in Biodental Engineering IV, 2017
Poly-e-caprolactone (PCL) and HA are nontoxic to cells, and commonly used in clinical situations. Positive effects of the addition of HA micro-particles to a micro-macroporous PCL matrix led to an increase of composite mechanical properties, and the calcium phosphate particles acted as a bioactive solid signal for bone-forming cells (Ciapetti et al. 2012). Biopolymers as poly(L-lactic acid) (PLLA), which are fabricated from renewable agriculture materials and then biodegraded back to water and carbon dioxide, have been used widely for bone tissue engineering. The polymer brushes poly(γ-benzyl-L-glutamate) (PBLG) are used to improve the compatibility between HA and PLLA, and thus have positive effect on the mechanical properties. PBLG-g-HA/PLLA scaffolds induced higher levels of bone formation and showed little effect on osteoclastogenesis, confirming that the additional use of HA to PLLA scaffolds improve the osteoconduction of bone grafts (Liao et al. 2014).
Risedronate-loaded aerogel scaffolds for bone regeneration
Published in Drug Delivery, 2023
Nahla El-Wakil, Rabab Kamel, Azza A. Mahmoud, Alain Dufresne, Ragab E. Abouzeid, Mahmoud T. Abo El-Fadl, Amr Maged
Amorphous cellulose (AmC), TEMPO-oxidized cellulose (NFC) and citric acid-cross-linked cellulose (NFC/AmC) nanofibers were prepared in this study. The properties of these nanofibers were examined using FTIR, X-ray diffractometry, and DSC. NFC and NFC/AmC showed dense and porous structures, while AmC showed an agglomerated, loose structure. The rigidity of NFC/AmC, due to its cross-linked structure, resulted in the formation of aerogel scaffolds with high brittleness and low compressibility compared to those prepared using NFC. All the fabricated aerogel scaffolds showed high porosity (above 90%). The addition of chitosan to NFC scaffolds slowed down the release of risedronate from them. The selected aerogel scaffolds prepared using NFC and chitosan were able to increase MG-63 cell proliferation and RUNX2 gene expression protein and, this effect increased when the scaffolds were loaded with risedronate. On the other hand, the presence of citric acid in chitosan-containing scaffolds decreased cell growth. These findings highlight the promising approach of using biopolymers produced from agro-wastes in pharmaceutical applications.
Localized, on-demand, sustained drug delivery from biopolymer-based materials
Published in Expert Opinion on Drug Delivery, 2022
Junqi Wu, Sawnaz Shaidani, Sophia K. Theodossiou, Emily J. Hartzell, David L. Kaplan
For the successful design and application of local drug delivery systems using naturally derived biopolymers, matching local tissue features, mechanical properties and local responses with the mechanical properties of the biopolymer-based materials is essential; for instance, softer biopolymer drug delivery systems such as hydrogels and sponges may be more appropriate for the brain, while mechanically robust systems such as films and thermoplastic molded implants may be better suited for orthopedic and dental tissues. Therefore, one of the important future directions should be focused on building a comprehensive database on the mechanical properties for biopolymers with different formats to match the local tissue environment. To propel the future development of biopolymer-based drug delivery systems, continued research to achieve sustained release, activated stimuli-responsive release, and mitigating the toxicity of drug for local healthy tissue are also important. In addition, continued investigation into the properties of natural biopolymers that prevent or minimize inflammatory responses are crucial moving forward. Finally, the commercial aspects for substituting synthetic polymers with biopolymers in pharmaceutical and medical devices related industries needs to be explored for future directions.
Fabrication of silver nanoparticles/gelatin hydrogel system for bone regeneration and fracture treatment
Published in Drug Delivery, 2021
Xingwen Han, Jingjing He, Zhan Wang, Zhongtian Bai, Peng Qu, Zhengdong Song, Wenji Wang
Nowadays, biopolymers receive greater attention in different areas like catalytic reactions, electrochemistry and specifically in biomedical applications (Selvam et al., 2017; Balaji et al., 2018). Gelatin is majorly applied in drug delivery systems owing to their strong biocompatibility. In detail, in order to enlarge the cell viability, a multiple layered composite coating was applied on Ag substrates (Cai et al., 2005). The results of an earlier report described the synthesis of gel-loaded nanotube substances to protect the biological activity of BMP2 (Hu et al., 2012). The individually synthesized multi-layer structure functioned as a biomimetic extracellular template that sustained the biomolecule release rate. However, no one has developed till now the unique fabrication of nanostructures tailored morphologically with bio-composited co-polymeric gel hydrogel to manage hard tissue nursing care and to accelerate bone fracture healing as per our knowledge.