Targeted modulation of immune cells and tissues using engineered biomaterials

Therapies modulating the immune system offer the prospect of treating a wide range of conditions including infectious diseases, cancer and autoimmunity. Biomaterials can promote specific targeting of immune cell subsets in peripheral or lymphoid tissues and modulate the dosage, timing and location of stimulation, thereby improving the safety and efficacy of vaccines and immunotherapies. Here, we review recent advances in biomaterials-based strategies, focusing on targeting of lymphoid tissues, circulating leukocytes, tissue-resident immune cells and immune cells at disease sites. These approaches can improve the potency and efficacy of immunotherapies by promoting immunity or tolerance against different diseases. This Review discusses biomaterials that promote therapeutic targeting of immune cells by modulating the dosage, timing and location of stimulation, thereby improving the safety and efficacy of vaccines and immunotherapies. Key points In immunotherapy, choosing the right target cell, tissue and treatment duration is essential to ensure effective immunomodulation while avoiding toxicity. Biomaterial-mediated targeting of immune cells in lymph nodes improves the potency and efficacy of vaccines by promoting immunity or tolerance. Circulating migratory immune cells can be targeted to perform as living chaperones to carry therapeutics into tissues. Systemic administration or intratumoral injection of nanomaterials and therapeutic depots can selectively accumulate and target immune cells in tumours. Reducing biomaterial complexity is essential to facilitate clinical translation.