Zhe Sun

Abstract Dental implants are the most common therapeutic approach for resolving tooth loss and damage. Despite technical advances in treatment, implant failure rates can be as high as 23% with the major cause of peri‐implantitis: a multi‐species bacterial infection. With an annual growth rate in implant placements of 8.78% per annum, implant failure caused by bacterial infection is a significant oral and general health issue. The rise in antibiotic resistance in oral bacteria further adds pressure to implant failure; thus, there is a need for adjunctive therapy to improve implant outcomes. Due to the broad spectrum of activity and a low risk of inducing bacterial resistance, peptide antibiotics are emerging as a promising implant coating material to reduce/prevent peri‐implantitis and improve dental implant success rates. In this review, we summarised the current strategies of coating antimicrobial peptides (AMPs) onto dental implant material surfaces with multi‐functional properties to enhance osteoblast growth and prevent bacterial infections. This review compared the recent reported literature on dental implant coating with AMPs, which will provide an overview of the current dental implant coating strategies using AMPs and insights for future clinical applications.

Vaccination is one of the most efficacious and cost-effective ways to protect people from infectious diseases and potentially cancer. The shift in vaccine design from disrupted whole pathogens to subunit antigens has brought attention on to vaccine delivery materials. For the last two decades, nanotechnology-based vaccines have attracted considerable attention as delivery vehicles and adjuvants to enhance immunogenicity, exemplified with the current COVID vaccines. The nanoparticle vaccines display unique features in protecting antigens from degradation, controlled antigen release and longer persisting immune response. Due to their size, shape and surface charge, they can be outstanding adjuvants to achieve various immunological effects. With the safety and biodegradable benefit of calcium phosphate nanoparticles (CaP NPs), they are an efficient carrier for vaccine design and adjuvants. Several research groups have studied CaP NPs in the field of vaccination with great advances. Although there are several reports on the overview of CaP NPs, they are limited to the application in biomedicine, drug delivery, bone regeneration and the methodologies of CaP NPs synthesis. Hence, we summarised the basic properties of CaP NPs and the recent vaccine development of CaP NPs in this review.

In vivo pharmacokinetics studies have shown that the proline-rich antimicrobial peptide, A3-APO, which is a discontinuous dimer of the peptide, Chex1-Arg20, undergoes degradation to small fragments at positions Pro6-Arg7 and Val19-Arg20. With the aim of minimizing or abolishing this degradation, a series of Chex1-Arg20 analogues were prepared via Fmoc/tBu solid phase peptide synthesis with D-arginine or, in some cases, peptide backbone N-methylated arginine, substitution at these sites. All the peptides were tested for antibacterial activity against the Gram-negative bacterium Klebsiella pneumoniae. The resulting activity of position-7 substitution of Chex1-Arg20 analogues showed that arginine-7 is a crucial residue for maintaining activity against K. pneumoniae. However, arginine-20 substitution had a much less deleterious effect on the antibacterial activity of the peptide. Moreover, none of these peptides displayed any cytotoxicity to HEK and H-4-II-E mammalian cells. These results will aid the development of more effective and stable PrAMPs via judicious amino acid substitutions.