现有的癌症治疗手段主要包括外科手术、放疗和化疗3种，但都面临着不同的问题和挑战。化疗会导致严重的毒副作用，放疗需避免射线辐射，外科手术很难多次操作，各种副作用也严重影响患者的有效存活率。而光动力疗法通过注射光敏药物，直接光照病灶，能够有针对性地杀死癌细胞，整个过程几乎无损，可以反复运用、长期治疗，是一种精准抗癌疗法。传统光动力疗法由可见光激发，很难穿透皮肤并深入组织。在已有的各类成功案例中，病灶通常是数毫米厚的扁平组织，而上转换光动力复合功能材料能够由长波段红外光激发诱导光动力治疗，从而将其适用范围提高到了厘米级别。因此，上转换光动力疗法能够作用于更多种类的组织器官，更重要的是能够治疗相对大型的肿瘤病灶。然而，对于红外窗口范围之外的深层组织和大型病灶，上转换光动力疗法仍有其劣势。随着纳米技术、低功耗集成电路和无线传能技术的发展，有望发展出长效可控的植入体技术：通过微创医学植入病灶区域并在体外遥控植入体进行深层光动力治疗；利用无线传能技术，可以反复激活该微型植入体，支持长期抗癌治疗直至康复，从而能够将个体化精准光动力抗癌疗法提升到一个全新的高度。%The conventional techniques for cancer treatment include chemotherapy, radiotherapy, and surgery. However, chemotherapy often brings systemic side-effects, radiation therapy is limited by the cumulative radiation dose, and surgical resection of tumors is not suitable for repeated therapy. Photodynamic therapy (PDT) is an emerging precise intervention for cancer treatment, but it is yet limited to superficial lesions because of low penetration of visible light. Recently, upconversion technology was proposed as a transferring agent for PDT. It is excited by near infrared (NIR) and able to emit visible light. Without toxicity, NIR is good at tissue penetration. Therefore, upconversional PDT (UPDT) is very useful for treating solid and large tumors. One of the remaining issues is that most cancerous lesions lie inside human body and beneath deep tissues. In other words, they are still out of NIR penetration. The development of micro/nano circuits and systems for wireless power implants is studied in this paper, which are possibly employed for long-term PDT of deeply situated tumors. Furthermore, it is possible to remote control these implants that are directly placed nearby cancerous lesions. Once integrated with UPDT, such wireless power implants are capable of treating deeply situated large tumors. In conclusion, this new technology is promising to advance UPDT for precise tumor treatment.
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