Injectable drug loaded gelatin based scaffolds as minimally invasive approach for drug delivery system: CNC / PAMAM nanoparticles

Abstract Drug delivery systems have been employed to increase efficiency of scaffolds designed for tissue engineering targets, especially remediating an injury. One step even further is utilizing injectable materials to eliminate the need for a second injury in a less invasive manner. The aim of this study is preparation and evaluation of preformed injectable cryogel to overcome fluid leakage of in situ formed hydrogels. For this reason, gelatin was chosen as the main component to resemble the natural extracellular matrix. When it comes to drug nomination, betamethasone sodium phosphate was chosen since severe inflammation response is one of the main reasons for prolong healing. For drug delivery part, two different carriers namely cellulose nanocrystal (CNC) and polyamidoamine (PAMAM) dendrimer were used. It was hypothesized that these nanocarriers not only provide a sustained release of the drug but also boost up mechanical properties. Therefore, prepared samples were characterized chemically, physically and biologically. Based on the results, highly branched nanocarrier (i.e. PAMAM) showed better behavior in mechanical properties (E=14 kPa) and drug delivery (loading efficiency=70% and sustain release in 24 h) rather than nanorod carrier (i.e. CNC) with E=11kPa and 65% loading efficiency. However, both nanocarriers significantly decrease the rate of degradation almost two times. It seems likely the above mentioned properties as well as the advantage of high cell viability (99 % and 105% for CNC and PAMAM incorporated samples respectively) makes the prepared samples a useful alternatives for minimally invasive drug delivery as a tool for tissue engineering applications.