Advanced cryopreservation engineering strategies:the critical step to utilize stem cell products

With the rapid development of stem cell-related therapies and regenerative medicine,the clinical application of stem cell products is on the rise.However,ensuring the effectiveness of these products after storage and transportation remains a challenge in the transformation to clinical trials.Cryopreservation technology allows for the long-term storage of cells while ensuring viability,making it a top priority for stem cell preservation.The field of cryopreservationrelated engineering technologies is thriving,and this review provides an overview of the background and basic principles of cryopreservation.It then delves into the main bioengineering technologies and strategies used in cryopreservation,including photothermal and electromagnetic rewarming,microencapsulation,and synergetic ice inhibition.Finally,the current challenges and future prospects in the field of efficient cryopreservation of stem cells are summarized and discussed.

Engineered extracellular vesicles enable high-efficient delivery of intracellular therapeutic proteins

Developing an intracellular delivery system is of key importance in the expansion of protein-based therapeutics acting on cytosolic or nuclear targets.Recently,extracellular vesicles(EVs)have been exploited as next-generation delivery modalities due to their natural role in intercellular communication and biocompatibility.However,fusion of protein of interest to a scaffold represents a widely used strategy for cargo enrichment in EVs,which could compromise the stability and functionality of cargo.Herein,we report intracellular delivery via Ev-based approach(IDEA)that efficiently packages and delivers native proteins both in vitro and in vivo without the use of a scaffold.As a proof-of-concept,we applied the IDEA to deliver cyclic GMP-AMP synthase(cGAS),an innate immune sensor.The results showed that cGAS-carrying EVs activated interferon signaling and elicited enhanced antitumor immunity in multiple syngeneic tumor models.Combining cGAS EVs with immune checkpoint inhibition further synergistically boosted antitumor efficacy in vivo.Mechanistically,scRNA-seq demonstrated that cGAS EVs mediated significant remodeling of intratumoral microenvironment,revealing a pivotal role of infiltrating neutrophils in the antitumor immune milieu.Collectively,IDEA,as a universal and facile strategy,can be applied to expand and advance the developmentof protein-based therapeutics.

Effect of baffle injectors on the first-order tangential acoustic mode in a cylindrical combustor

Combustion instability is a very important issue in the development of the propulsion systems used in aerospace. It is very important to associate the high frequency combustion instabilities with the acoustic characteristics of the combustion chamber. In this paper, the effects of various baffle injectors which were installed on the injector faceplate on the first-order tangential acoustic mode were investigated theoretically and experimentally. The effects of the gap between adjacent injectors on the first-order tangential acoustic mode in a cylindrical chamber were considered. The acoustic admittance of the injectors was derived. The results showed that the amplitude and frequency of the first-order tangential acoustic mode increase with the increase in the gap between adjacent injectors, but decrease with the increase in the number and height of the baffles.The baffle injectors have a greater influence on the amplitude and frequency of the first-order tangential acoustic mode than the baffle blades.