NIR light-assisted phototherapies for bone-related diseases and bone tissue regeneration: A systematic review

Abstract

Recently, the rapid development of biomaterials has induced great interest in the precisely targeted treatment of bone-related diseases, including bone cancers, infections, and inflammation. Realizing noninvasive therapeutic effects, as well as improving bone tissue regeneration, is essential for the success of bone‑related disease therapies. In recent years, researchers have focused on the development of stimuli-responsive strategies to treat bone-related diseases and to realize bone regeneration. Among the various external stimuli for targeted therapy, near infrared (NIR) light has attracted considerable interests due to its high tissue penetration capacity, minimal damage toward normal tissues, and easy remote control properties. The main objective of this systematic review was to reveal the current applications of NIR light-assisted phototherapy for bone-related disease treatment and bone tissue regeneration. Database collection was completed by June 1, 2020, and a total of 81 relevant studies were finally included. We outlined the various therapeutic applications of photothermal, photodynamic and photobiomodulation effects under NIR light irradiation for bone‑related disease treatment and bone regeneration, based on the retrieved literatures. In addition, the advantages and promising applications of NIR light-responsive drug delivery systems for spatiotemporal-controlled therapy were summarized. These findings have revealed that NIR light-assisted phototherapy plays an important role in bone-related disease treatment and bone tissue regeneration, with significant promise for further biomedical and clinical applications.

Keywords: Near infrared light; bone tissue regeneration; bone-related diseases; drug delivery systems; phototherapy.

Figure 1

Flowchart for the study screening and selection process, and reasons for inclusion/exclusion. N = number of publications. NIR, near infrared.

Figure 2

A pie chart representing the number and distribution of different applications of NIR light-assisted phototherapies in the included articles. NIR, near infrared.

Figure 3

A summary of the current most commonly used NIR light-responsive nanomaterials. NIR, near infrared.

Figure 4

Schematic illustration showing the applications of NIR light-responsive nanomaterials, NIR light-responsive bone scaffolds, and NIR light-triggered drug delivery systems for bone cancer therapy. The NIR light-responsive nanomaterials (A) and scaffolds (B) with the specific features of highly efficient photothermal conversion and controllable ROS release provide an effective biomaterial platform for the phototherapy of bone cancers. C. The NIR light-triggered drug delivery systems can realize controlled release of the encapsulated anti-tumor drugs for bone cancer chemotherapy. NIR, near infrared; ROS, reactive oxygen species.

Figure 5

Schematic illustration revealing the mechanisms of NIR light-assisted phototherapy for bone infection and inflammation. A. NIR light-induced hyperthermia increases the bacterial membrane permeability under ROS stimulation, accelerating the eradication of the biofilm formed on the surface of the implants. B. The NIR light can penetrate the inflamed joints and generate local heat and ROS to eliminate inflamed tissues, decreasing the generation of inflammatory cytokines, synovial erosion, and tissue destruction. NIR, near infrared; ROS, reactive oxygen species.

Figure 6

Schematic illustration of the NIR light-induced photobiomodulation, photothermal effect, and NIR light-triggered osteogenic molecule release systems to regulate new bone formation. A. Photobiomodulation therapy under NIR light irradiation can modulate the attachment, proliferation, and differentiation of stem cells. B. Phototherapy based on the NIR light-responsive nanomaterials can induce mild local heat under NIR light irradiation, which enhances new bone formation. C. NIR light‑responsive release systems can realize the controlled release of osteogenic molecules, such as ions, drugs, and cytokines, to accelerate new bone formation. NIR, near infrared.