Piezoelectric Biomaterials Inspired by Nature for Applications in Biomedicine and Nanotechnology.

Bioelectricity provides electrostimulation to regulate cell/tissue behaviors and functions. In the human body, bioelectricity can be generated in electromechanically responsive tissues and organs, as well as biomolecular building blocks that exhibit piezoelectricity, with a phenomenon known as the piezoelectric effect. Inspired by natural bio-piezoelectric phenomenon, efforts have been devoted to exploiting high-performance synthetic piezoelectric biomaterials, including molecular materials, polymeric materials, ceramic materials, and composite materials. Notably, piezoelectric biomaterials polarize under mechanical strain and generate electrical potentials, which can be used to fabricate electronic devices. Herein, a review article is proposed to summarize the design and research progress of piezoelectric biomaterials and devices toward bionanotechnology. First, the functions of bioelectricity in regulating human electrophysiological activity from cellular to tissue level are introduced. Next, recent advances as well as structure-property relationship of various natural and synthetic piezoelectric biomaterials are provided in detail. In the following part, the applications of piezoelectric biomaterials in tissue engineering, drug delivery, biosensing, energy harvesting, and catalysis are systematically classified and discussed. Finally, the challenges and future prospects of piezoelectric biomaterials are presented. It is believed that this review will provide inspiration for the design and development of innovative piezoelectric biomaterials in the fields of biomedicine and nanotechnology.

Stimuli-responsive peptide hydrogels for biomedical applications.

Stimuli-responsive hydrogels can respond to external stimuli with a change in the network structure and thus have potential application in drug release, intelligent sensing, and scaffold construction. Peptides possess robust supramolecular self-assembly ability, enabling spontaneous formation of nanostructures through supramolecular interactions and subsequently hydrogels. Therefore, peptide-based stimuli-responsive hydrogels have been widely explored as smart soft materials for biomedical applications in the last decade. Herein, we present a review article on design strategies and research progress of peptide hydrogels as stimuli-responsive materials in the field of biomedicine. The latest design and development of peptide hydrogels with responsive behaviors to stimuli are first presented. The following part provides a systematic overview of the functions and applications of stimuli-responsive peptide hydrogels in tissue engineering, drug delivery, wound healing, antimicrobial treatment, 3D cell culture, biosensors, etc. Finally, the remaining challenges and future prospects of stimuli-responsive peptide hydrogels are proposed. It is believed that this review will contribute to the rational design and development of stimuli-responsive peptide hydrogels toward biomedical applications.

Self-Assembling Peptide-Based Functional Biomaterials.

Peptides can self-assemble into various hierarchical nanostructures through noncovalent interactions and form functional materials exhibiting excellent chemical and physical properties, which have broad applications in bio-/nanotechnology. The self-assembly mechanism, self-assembly morphology of peptide supramolecular architecture and their various applications, have been widely explored which have the merit of biocompatibility, easy preparation, and controllable functionality. Herein, we introduce the latest research progress of self-assembling peptide-based nanomaterials and review their applications in biomedicine and optoelectronics, including tissue engineering, anticancer therapy, biomimetic catalysis, energy harvesting. We believe that this review will inspire the rational design and development of novel peptide-based functional bio-inspired materials in the future.

Development of anticancer peptides with low hemolysis, high penetrating membrane activity, certain analgesic activity and the synergistic anticancer effect.

Herein, an amphiphilic cationic α-helical anticancer lipopeptide, P10 with low toxicity and high penetrating membrane activity was developed. This lipopeptide could self-assemble into stable spherical aggregates in aqueous solution and encapsulate Dox with a hydrophobic structure to form the P10@Dox nanomedicine. The Dox encapsulation efficiency was 81.3% ± 3.48% and its release from the P10@Dox nanomedicine had the characteristics of slow release and pH response. The in vitro experiments showed that the P10 lipopeptide had low toxicity, excellent membrane penetrating activity and high serum stability, the release of Dox from P10@Dox in cells was time and concentration dependent, and the P10@Dox nanomedicine played a good anti-cancer role. The animal experiments and tissue sections showed that the P10 lipopeptide and P10@Dox nanomedicine both had low hemolysis, and P10@Dox nanomedicine not only greatly reduced the toxicity and side effects of Dox, but also effectively inhibited the tumor growth. Additionally, it was surprising that P10 exhibited certain analgesic activity, which could reduce the accompanying cancer pain, while playing an effective role in cancer therapy. Thus, the results showed that the P10 lipopeptide can be used as an ideal drug carrier and it has great application potential in the field of clinical cancer therapy.

Synthesis of ß-cyclodextrin-PEG-G molecules to delay tumor growth and application of ß-cyclodextrin-PEG-G aggregates as drug carrier.

The clinical use of many chemotherapeutic drugs is considerably greatly limited due to their serious side effects. This problem can be solved by using a low-toxic or nontoxic drug carrier that exhibits excellent performance in entrapping chemotherapeutic drugs. Accordingly, ß-cyclodextrin-PEG-guanosine (ß-CD-PEG-G) molecule was first synthesized. The molecules can self-assemble into negatively charged spherical aggregates (called ß-CD-PEG-G aggregates) that can stably exist in an aqueous solution and entrap doxorubicin (Dox) to form ß-CD-PEG-G-Dox nanomedicine. Dox encapsulation efficiency is approximately 79 ± 6.3%. Dox from ß-CD-PEG-G-Dox nanomedicine exhibits sustained release and pH responsiveness. Cell and animal experiments showed that ß-CD-PEG-G-Dox nanomedicine could effectively induce cancer cell apoptosis to exert antitumor activity. Unexpectively, the animal experiment and tissue sections demonstrated that ß-CD-PEG-G aggregates exhibit certain antitumor activity that could delay the tumor growth. Therefore, the ß-CD-PEG-G molecule has high potential as a drug carrier candidate.

Construction of a Drug Delivery System and Photodynamic Therapy Reagent Based on the Biotin-HSA-DDA-TCPP Molecules and the Application of Synergistic Antitumor Effect.

A biotin-HSA-DDA-TCPP molecule, which can be used as a photodynamic therapeutic agent and drug carrier, was synthesized. The molecule can self-assemble into spherical aggregates, which can be loaded with Dox to form biotin-HSA-DDA-TCPP-Dox nanoparticles in aqueous solution, and the Dox loading efficiency was 86.6 ± 1.76%. The Dox's release behavior was pH responsive and has a sustained release. Cell experiments showed that biotin-HSA-DDA-TCPP-Dox nanoparticles could effectively induce cancer cell apoptosis to exert anticancer and photodynamic therapy effects. The results of animal experiments, tissue sections, and blood biochemistry tests showed that the biotin-HSA-DDA-TCPP-Dox nanoparticles could exert the effect of photodynamic therapy and antitumor, which is similar to Dox after laser irradiation, and achieve a synergistic antitumor effect. The nanoparticles can significantly reduce the Dox toxicity and increase the circulation time of the drug in the body. In summary, the biotin-HSA-DDA-TCPP molecule, which combines the advantages of photodynamic therapy and drug carrier, has great potential in clinical application.