Light-based 3D printing of stimulus-responsive hydrogels forminiature devices:recent progress and perspective

Miniature devices comprising stimulus-responsive hydrogels with high environmental adaptability are now considered competitive candidates in the fields of biomedicine,precise sensors,and tunable optics.Reliable and advanced fabricationmethods are critical formaximizing the application capabilities ofminiature devices.Light-based three-dimensional(3D)printing technology offers the advantages of a wide range of applicable materials,high processing accuracy,and strong 3D fabrication capability,which is suitable for the development of miniature devices with various functions.This paper summarizes and highlights the recent advances in light-based 3D-printed miniaturized devices,with a focus on the latest breakthroughs in lightbased fabrication technologies,smart stimulus-responsive hydrogels,and tunable miniature devices for the fields of miniature cargo manipulation,targeted drug and cell delivery,active scaffolds,environmental sensing,and optical imaging.Finally,the challenges in the transition of tunable miniaturized devices from the laboratory to practical engineering applications are presented.Future opportunities that will promote the development of tunable microdevices are elaborated,contributing to their improved understanding of these miniature devices and further realizing their practical applications in various fields.

Oral administration microrobots for drug delivery

Oral administration is the most simple, noninvasive, convenient treatment. With the increasing demands on thetargeted drug delivery, the traditional oral treatment now is facing some challenges: 1) biologics how toimplement the oral treatment and ensure the bioavailability is not lower than the subcutaneous injections;2)How to achieve targeted therapy of some drugs in the gastrointestinal tract? Based on these two issues, drugdelivery microrobots have shown great application prospect in oral drug delivery due to their characteristics offlexible locomotion or driven ability. Therefore, this paper summarizes various drug delivery microrobotsdeveloped in recent years and divides them into four categories according to different driving modes: magneticcontrolleddrug delivery microrobots, anchored drug delivery microrobots, self-propelled drug delivery microrobotsand biohybrid drug delivery microrobots. As oral drug delivery microrobots involve disciplines such asmaterials science, mechanical engineering, medicine, and control systems, this paper begins by introducing thegastrointestinal barriers that oral drug delivery must overcome. Subsequently, it provides an overview of typicalmaterials involved in the design process of oral drug delivery microrobots. To enhance readers’ understanding ofthe working principles and design process of oral drug delivery microrobots, we present a guideline for designingsuch microrobots. Furthermore, the current development status of various types of oral drug delivery microrobotsis reviewed, summarizing their respective advantages and limitations. Finally, considering the significantconcerns regarding safety and clinical translation, we discuss the challenges and prospections of clinical translationfor various oral drug delivery microrobots presented in this paper, providing corresponding suggestions foraddressing some existing challenges.