18The increasing prevalence of wound infections caused by antibiotic resistant bacteria is an urgent 19 challenge facing modern medicine. To address this issue the expedient use of antimicrobial metals 20 such as zinc, copper and silver were incorporated into an FDA-approved polymer (polycaprolactone -21 PCL) to produce filaments for 3D printing. These metals have broad-spectrum antimicrobial 22properties, and moreover, copper and zinc can enhance the wound healing process. 3D scanning 23 was used to construct 3D models of a nose and ear to provide the opportunity to customize shape 24 and size of a wound dressing to an individual patient. Hot melt extrusion was used to extrude pellets 25 obtained by vacuum-drying of solutions of PCL and the different metals in order to manufacture 26 metal-homogeneously-loaded filaments. Wound dressings with different shapes were produced with 27 the filaments containing different concentrations of metals. Release of the metals from the dressings 28 was determined by inductively coupled plasma atomic emission spectroscopy. All the different metal 29 dressings show fast release (up to 24 h) followed by slow release (up to 72 h). The antibacterial 30 efficacy of the wound dressings was tested using a thermal activity monitor system, revealing that 31 silver and copper wound dressings had the most potent bactericidal properties. This study shows 32 that 3D scanning and 3D printing, which are becoming simpler and more affordable, have the 33 potential to offer solutions to produce personalised wound dressings.

Three-dimensional (3D) chemical models are a well-established learning tool used to enhance the understanding of chemical structures by converting two-dimensional paper or screen outputs into realistic three-dimensional objects. While commercial atom model kits are readily available, there is a surprising lack of large molecular and orbital models that could be used in large spaces. As part of a program investigating the utility of 3D printing in teaching, a modular size-adjustable molecular model and orbital kit was developed and produced using 3D printing and was used to enhance the teaching of stereochemistry, isomerism, hybridization, and orbitals.

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