Mesoporous bioactive nanocarriers in electrospun biopolymer fibrous scaffolds designed for sequential drug delivery

Here we communicate a novel design to deliver multiple drugs from scaffolds which have special therapeutic efficacy for the repair and regeneration of hard tissues. A sequential release of multiple drugs (a rapid release of drug 1 accompanied by a slow release of drug 2) was enabled by pre-loading drug 2 within mesoporous bioactive glass nanospheres (mBGn) which were added up to 30% to a polymer (polycaprolactone–gelatin) fiber matrix that has also encapsulated drug 1. In particular, excellent bioactive properties of mBGn, i.e., induction of bone mineral-like apatite formation and release of therapeutic ions (calcium and silicon) potentiate the usefulness of the mBGn-added scaffolds for bone regeneration. Proof-of-concept study utilizing two model drugs within the mBGn-added fiber (procaine hydrochloride (PCH) in mBGn and tetracycline hydrochloride (TCH) in nanofiber) demonstrated a typical sequential release pattern of the drugs, i.e., a rapid release of TCH within 24 h while a sustainable and long-term release of PCH over weeks to a month. Although biological efficacy of the drug-delivering scaffolds warrants further study, this finding suggests the mBGn-added polymer fiber may be a potential therapeutic matrix for bone regeneration.