Poloxamer is a triblock copolymer with amphiphilicity and reversible thermal responsiveness and has wide application prospects in biomedical applications owing to its multifunctional properties. Poloxamer hydrogels play a crucial role in the field of tissue engineering and have been regarded as injectable scaffolds for loading cells or growth factors (GFs) in the last few years. Hydrogel micelles can maintain the integrity and stability of cells and GFs and form an appropriate vascular network at the application site, thus creating an appropriate microenvironment for cell growth, nerve growth, or bone integration. The injectability and low toxicity of poloxamer hydrogels make them a noninvasive method. In addition, they can also be good candidates for bio-inks, the raw material for three-dimensional (3D) printing. However, the potential of poloxamer hydrogels has not been fully explored owing to the complex biological challenges. In this review, the latest progress and cutting-edge research of poloxamer-based scaffolds in different fields of application such as the bone, vascular, cartilage, skin, nervous system, and organs in tissue engineering and 3D printing are reviewed, and the important roles of poloxamers in tissue engineering scaffolds are discussed in depth.

Owing to the limitations of traditional systemic drug delivery in the treatment of bone diseases with side effects on normal cells, the selection of materials with high affinities for bones, as targeting ligands to modify drug carriers, has become an important research topic. Tetracyclines (TCs) have an adsorption effect on hydroxyapatite (HAp). Thus, they can be used as bone-targeting ligands and combined with drug carriers. In this study, density functional theory is used to analyze the interaction mechanism of TC, oxytetracycline (OTC), chlortetracycline, and HAp. We calculate the electrostatic potential (ESP) and molecular orbitals to predict the possible binding sites of TCs on the HAp surface. The adsorption energy is used to compare the affinities of the three TCs to HAp. An independent gradient model analysis is performed to study the weak interaction between TCs and HAp. The coordination bond between TCs and the HAp surface is evaluated by conducting a charge density difference analysis. The results show that OTC has the highest affinity to HAp because the introduction of hydroxyl groups change the adsorption configuration of OTC. Thus, OTC adsorbed on HAp in a broken-line shape exposes more binding sites. This study provides a theoretical basis for TCs as bone-targeting ligands in treating bone diseases and in improving the safety of treatment by selecting different bone-targeting ligands.